This is CNBC's live blog tracking developments on the war in Ukraine. See below for the latest updates. 

Ukrainian President Volodymyr Zelenskyy said "tough fights" are continuing as Ukraine continues its counteroffensive, having acknowledged that progress is slower than expected.

In his nightly address Wednesday, Zelenskyy first focused on the war, saying there were "tough fights" in the south and east of the country

In the counteroffensive in southern Ukraine there was "movement forward," he said, while in the east of the country, the defense was holding. Ukraine says it has so far reclaimed eight villages in the southern region of Zaporizhzhia over the past two weeks of counteroffensive.

In an interview published by the BBC Wednesday, Zelenskyy conceded that the progress of Ukrainian counteroffensive has been "slower than desired."

Russian President Vladimir Putin said Wednesday that Ukraine's counteroffensive was in a "lull" as it struggles to suffer heavy losses of personnel and equipment.

Defense analysts at the Institute for the Study of War pointed out, however, that Putin then "preposterously" claimed that Russian forces had destroyed 244 tanks and 679 armored vehicles since counteroffensive operations began in early June.

Build military strategy 'on reality,' Putin tells security officials

We have some lines coming out of Russian President Vladimir Putin's meeting with Russia's Security Council Thursday morning:

Clips of the meeting posted on the Zarubin Telegram channel show Putin commenting on personnel and equipment losses for Ukraine and destroyed Western military hardware.

Putin claimed Ukraine lost as many as 13,000 troops during the counteroffensive over the last few weeks, saying that figure was "a summary from all the figures that we have received," he said in comments translated by NBC News. He did not detail how the figures were sourced.

On destroyed Western weaponry and ammunition, Putin said that out of 246 tanks that Moscow claims have been destroyed since the start of the counteroffensive, which Russia says began on June 4, 13 of them were Western-made. Again, Putin did not present evidence to back his assertion.

Russia has frequently framed the war in Ukraine as a proxy war in which the West is fighting Russia. Putin reiterated that sentiment Thursday, saying that "weaponry can, of course, be supplied in excess but mobilization capacities are, however, not infinite." Putin said Ukraine appears to have reserves that haven't been used.

"And it appears that the Western allies of Ukraine have indeed decided to fight with Russia up until the last Ukrainian. We should also consider that the offensive [counter-offensive] potential of the enemy is not yet depleted, multiple strategic reserves have not been utilized. So I ask you to take this into account in building your [strategies] as they should be built on reality," Putin said.

— Holly Ellyatt

Ukraine says Russia considering 'terrorist attack' on Zaporizhzhia nuclear plant

Ukraine's President Volodymyr Zelenskyy said he's been warned by the country's intelligence services that Russia is considering carrying out a "terrorist attack" on the Zaporizhzhia nuclear power plant that it's currently occupying in southern Ukraine.

Posting on Telegram, Zelenskyy said "intelligence has received information that Russia is considering the scenario of a terrorist act at the Zaporizhzhia nuclear plant - a terrorist act with the release of radiation. They have prepared everything for this," he said, without giving further detail on the evidence underlying the intelligence.

"Unfortunately, I had to be reminded more than once that radiation knows no national borders and who it hits is determined only by the direction of the wind," he said.

The Kremlin responded to the allegation Thursday by calling it "another lie," state news agency TASS reported.

Russian forces have occupied the Zaporizhzhia nuclear power plant since March 2022, early on in the invasion, and it has frequently been at the center of hostilities, stoking fears of a possible nuclear catastrophe. The site is still occupied but also has inspectors from the International Atomic Energy Agency visiting it to monitor safety at the facility.

Zelenskyy said all available information would be shared with its allies, saying "all countries, absolutely everyone should know this. International organizations. All of them."

"There should never be any terrorist attacks on nuclear power plants, anywhere. This time it should not be like with Kakhovka" he said, referring to the Kakhovka Dam that Ukraine accused Russia of blowing up, causing widespread flooding. Russia accused Ukraine of sabotaging the dam.

— Holly Ellyatt

Ukraine strikes bridge to Crimea, Russian officials say

Russian officials claimed Thursday that Ukrainian missiles had struck the Chonhar road bridge connecting Russian-occupied Crimea with the southern Ukrainian region of Kherson.

Traffic using the Chongar bridge (as Russia spells it) had to be temporarily diverted, news agency RIA Novosti reported, citing Crimea's transport ministry.

"Due to damage to the roadbed on the Chongar bridge, traffic flows have been temporarily redirected to the Armyansk and Perekop checkpoints. These checkpoints are operating normally," the ministry said, RIA Novosti reported.

The bridge is one of several important routes into mainland Ukraine from the Crimean peninsula and is used by the Russian military to move personnel and supplies.

Earlier, Sergey Aksenov, the Russian-installed head of Crimea, said earlier on Telegram that "at night, a blow was struck on the Chongar bridge. There were no casualties."

"At the moment, explosive experts are conducting an examination to assess the type of ammunition," he added.

Vladimir Saldo, the Russian-installed governor of Kherson, said the missile damage was "another completely senseless action carried out by the Kyiv regime on orders from London," having said in a previous post that preliminary information suggested British "Storm Shadow" missiles had been used.

Saldo said the apparent attack "will not affect the course of the special operation in any way - there are other land routes to the Crimea."

He added that Russia "was taking measures to eliminate damage to bridge crossings."

Ukraine has not commented on the incident, and has not commented on previous incidents of apparent sabotage to routes — such as the high-profile Kerch Strait bridge — used by Russian forces to access Crimea, which it annexed in 2014, and the Russian mainland.

— Holly Ellyatt

Macron would be inappropriate guest at BRICS summit, says Russia

French President Emmanuel Macron would be an inappropriate guest at the BRICS summit, the RIA news agency quoted Russian Deputy Foreign Minister Sergei Ryabkov as saying on Thursday, criticising countries whose policies Russia considers hostile.

The BRICS group of emerging economies, comprising Brazil, Russia, India, China and South Africa, is due to hold a summit in Johannesburg in August.

Asked about Macron's reported desire to attend the summit, Ryabkov said: "Clearly, leaders of states that pursue such a hostile and unacceptable policy towards us, discussing with such emphasis and conviction that Russia should be isolated on the international stage, and share the common NATO line on inflicting a so-called strategic defeat on us - such a leader is an inappropriate BRICS guest.

"And we are not hiding this approach of ours, we have told our colleagues from South Africa. We expect that our point of view will be fully accepted," Ryabkov was quoted as saying.

South Africa is currently mulling its legal options if Russian President Vladimir Putin decides to attend the BRICS summit because the International Criminal Court (ICC) in March issued an arrest warrant for Putin over the Ukraine conflict.

South Africa is an ICC member and would theoretically be required to arrest him if he attends the BRICS summit.

— Reuters

Putin's latest war claim deemed preposterous by defense analysts

Russian President Vladimir Putin said Wednesday that Ukraine's counteroffensive is in a "lull" as it struggles with heavy losses.

Speaking to a journalist in the Kremlin Wednesday, Putin claimed that the slowdown in the counteroffensive was "due to the fact that the enemy suffers serious losses - both in personnel and in equipment."

Defense analysts at the Institute for the Study of War pointed out, however, that Putin then "preposterously" claimed that Russian forces had destroyed 244 tanks and 679 armored vehicles since counteroffensive operations began in early June.

The ISW noted that while Russian forces' "doctrinally sound defense in western Zaporizhia and prepared defensive positions throughout southern Ukraine are likely slowing Ukrainian advances," the pace of counteroffensive operations "is not emblematic of Ukraine's wider offensive potential and Ukrainian forces are likely successfully setting conditions for a future main effort despite initial setbacks." 

Ukrainian officials have long signaled that the Ukrainian counteroffensive "would be a series of gradual and sequential offensive actions," the ISW noted, and have more recently observed that "currently ongoing operations do not represent the main thrust of Ukraine's counteroffensive planning."

— Holly Ellyatt

Tough fighting continuing in 'slower than desired' counteroffensive, Zelenskyy says

Ukrainian President Volodymyr Zelenskyy said "tough fights" are ongoing as Ukraine continues its counteroffensive, having acknowledged that progress is slower than expected.

In his nightly address Wednesday, Zelenskyy first focused on the war, saying there are "Tough fights. South – we destroy the enemy. Donetsk region – we are destroying the enemy. Kupiansk direction – no matter what Russian terrorists plan, we will destroy the enemy."

In the counteroffensive in southern Ukraine, "there is our movement forward," he said, while in the east of the country, the defense is holding. Ukraine says it has so far reclaimed eight villages predominantly in the southern region of Zaporizhzhia over the past two weeks of counteroffensive.

In an interview published by the BBC Wednesday, Zelenskyy conceded that the progress of Ukrainian counteroffensive has been "slower than desired."

"Some people believe this is a Hollywood movie and expect results now. It's not," he said. "What's at stake is people's lives."

"Whatever some might want, including attempts to pressure us, with all due respect, we will advance on the battlefield the way we deem best," he added.

The president noted that Ukrainian advances are not easy because Russian forces have mined 200,000 square kilometers (77,220 sq miles) of front-line territory.

On Wednesday, Russian President Vladimir Putin claimed that there was a "lull" in the counteroffensive.

— Holly Ellyatt

Kyiv reiterates calls to join NATO alliance

The chief of Ukrainian President Volodymyr Zelenskyy's office reiterated calls that Kyiv should ascend to the NATO military alliance.

"Ukraine should be in NATO. This will save Europe from a major war," Andrii Yermak wrote on his official Telegram channel, according to an NBC News translation. 

Zelenskyy began an expedited process of applying to the world's most powerful military alliance in late September.

— Amanda Macias

Putin says Russia's new Sarmat nuclear missiles soon ready for deployment

President Vladimir Putin said on Wednesday that Russia's new generation of Sarmat intercontinental ballistic missiles, which are capable of carrying 10 or more nuclear warheads, would soon be deployed for combat duty.

In a speech to new graduates of military academies, Putin stressed the importance of Russia's "triad" of nuclear forces that can be launched from land, sea or air.

"The most important task here is the development of the nuclear triad, which is a key guarantee of Russia's military security and global stability," he said.

"Already about half of the units and formations of the Strategic Missile Forces are equipped with the latest Yars systems, and the troops are being re-equipped with modern missile systems with the Avangard hypersonic warhead."

The first Sarmat launchers would be put on combat duty "in the near future", Putin said.

— Reuters

Kremlin says Biden calling Xi a 'dictator' reveals foreign policy contradictions

The Kremlin said U.S. President Joe Biden calling his Chinese counterpart Xi Jinping a "dictator" shortly after a high-profile meeting between U.S. and Chinese officials shows confusion in the White House's foreign policy.

Biden's comment at a Tuesday fundraiser came just a day after Secretary of State Antony Blinken wrapped up his first official visit to Beijing.

Referring to Biden's remark, Kremlin Press Secretary Dmitry Peskov said "on the one hand, of course, this is a very contradictory manifestation of U.S. foreign policy, which speaks of a large element of unpredictability," he told reporters, according to a NBC translation.

"And on the other hand, the continuation of such mentoring manifestations of U.S. foreign policy, which have already become unacceptable for a huge number of states and the number of these states is constantly growing," he added.

"However, this is their business. We have our own bad relations with the United States of America and its very good relations with the People's Republic of China," Peskov said.

Blinken's visit to Beijing on Monday took place at a time of high tension between the U.S. and China, with Beijing's close relationship with Moscow a concern for the West.

Biden's "dictator" comment is bound to fray relations further and on Wednesday, China responded by saying the comment was "ridiculously absurd."

— Holly Ellyatt

West pledges billions to Ukraine at rebuilding conference

Britain, the United States and the European Union pledged on Wednesday billions of dollars more help to rebuild Ukraine, with British Prime Minister Rishi Sunak launching a war insurance framework to try to spur companies to invest.

While welcoming the support, the answer from Ukrainian President Volodymyr Zelenskyy was blunt - Kyiv needs concrete commitments to projects that will help Ukraine not only recover but to develop into a powerful member of the Western world.

After nearly 16 months of a war that has destroyed homes, hospitals and other critical infrastructure across Ukraine, Sunak appealed to businesses and governments at a recovery conference in London to do more to help rebuild the country.

Addressing the key difficulty for most companies wanting to invest in Ukraine - insurance against war damage and destruction - Sunak announced the London Conference Framework for War Risk insurance, which could pave the way for derisking investment, though he was light on details.

He said the London Conference Framework was "a huge step forward towards helping insurers to underwrite investments into Ukraine, removing one of the biggest barriers and giving investors the confidence they need to act".

Sunak also unveiled measures including $3 billion of additional guarantees to unlock World Bank lending that Ajay Banga, president of the World Bank Group, said would allow his group to continue to help "people rebuild their lives after devastation".

European Commission President Ursula von der Leyen said the EU would provide Ukraine with 50 billion euros for 2024-27, while U.S. Secretary of State Antony Blinken offered $1.3 billion in additional aid.

Ukraine is seeking up to $40 billion to fund the first part of a "Green Marshall Plan" to rebuild its economy, including developing a coal-free steel industry, a senior Ukrainian official said before the conference.

The total bill will be huge, with Ukraine, the World Bank, the European Commission and the United Nations estimating in March that the cost was at $411 billion for the first year of the war. It could easily reach more than $1 trillion.

— Reuters

Europe doesn't want to see a frozen conflict in Ukraine, European Commission head says

A ceasefire in Ukraine is not enough for European officials, who want lasting peace in the region, European Commission President Ursula von der Leyen told CNBC.

"We are very clear we do not want only a ceasefire and a frozen conflict in regions of Ukraine, because these regions will always be fragile. No investment will go there, and the conflict could [at] any time flare up again, as we have learned since 2014. So it has to be a real peace," von der Leyen said on the sidelines of the Ukraine Recovery Conference in London.

Speaking to CNBC's Steve Sedgwick, von der Leyen said that China can nevertheless be a crucial player in the peace process.

"China is a permanent member of the UN, and this comes with responsibility. And China has influence on Russia, so we expect China to use this influence to convince Russia to sit down at the negotiating table," she said.

Read more on the story here: 'We do not want only a ceasefire': EU chief calls for lasting peace in Ukraine

Russia resists counteroffensive, and Ukraine knows it faces a tough challenge

It's becoming clear that Ukraine could have a long and bloody slog ahead of it when it comes to its counteroffensive aiming at recapturing Russian-occupied territory in the south and east of the country.

Ukraine's counteroffensive has produced only limited gains so far, with eight settlements reclaimed in the last two weeks. Ukrainian officials are the first to admit that the country's armed forces face a "tough duel" with Russia in the weeks and months ahead.

"We knew from before we started [the counteroffensive] that this wasn't going to be a walk in the park," Yuriy Sak, a senior advisor in Ukraine's defense ministry, told CNBC Tuesday.

"We knew that Russians had months to prepare for it, we knew that they have built very, very strongly-fortified defense lines, that they have laid millions of mines along the front line. They're dug in so deep, that we already had a very good idea that this will be not an easy task," he added.

Read more on the story here: 'Tough duel' ahead for Ukraine as Russia mounts fierce resistance to counteroffensive

— Holly Ellyatt

Read CNBC's previous live coverage here:

Putin says new nuclear missiles ready to deploy soon; West pledges billions to help rebuild Ukraine