This was CNBC's live blog tracking developments on the war in Ukraine.

Ukraine formally started the screening process to begin talks over its future membership of the European Union on Thursday, President Volodymyr Zelenskyy said.

In a post on X, the Ukrainian leader said he welcomed the start of "substantial preparations for Ukraine's EU accession talks" in Brussels, following an agreement reached with EU Commission President Ursula von der Leyen last week at the World Economic Forum in Davos, Switzerland.

"The thorough work of assessing the conformity of Ukrainian legislation with EU norms, the formation of Ukraine's delegation, and our negotiating position are all ahead of us," Zelenskyy added.

"I expect full engagement of Ukrainian government team and the first intergovernmental conference to be held already this spring."

Across the Atlantic, bipartisan U.S. Senate negotiations over a border security deal that ties in aid for Ukraine have hit a critical juncture, Republican Senator John Thune told reporters on Thursday, according to Reuters. The White House said last week that the U.S. money supply to Ukraine has now run out, which could leave Kyiv ill-equipped to repel the Russian invasion.

A small bipartisan group of senators is seeking a way to please Republicans aligned with Donald Trump, the front-runner for the party's presidential candidacy, who has openly pressured allies not to compromise on legislation that would help President Joe Biden in the run-up to November's election.

Meanwhile, Moscow and Kyiv continue to trade allegations over the shooting down on Wednesday of a Russian military transport plane that was carrying 65 Ukrainian prisoners of war and nine Russians.

Russian President Vladirmir Putin on Friday said the aircraft was shot down by Ukrainian air defenses, either on purpose or by mistake.

In televised comments reported by Reuters, Putin said a Russian investigation into the incident would be published in two to three days, and that preliminary results suggested French or U.S. missiles were involved.

Photos show traces of destroyed Russian equipment on the outskirts of east Ukraine stronghold

Photos published via Getty Images show recently damaged Russian military equipment on the outskirts of Ukraine's industrial hub of Avdiivka, which is regarded as the gateway to Donetsk.

— Sam Meredith, Adam Jeffery

Russia extends detention of U.S. journalist Evan Gershkovich

A Moscow court on Friday extended the detention of U.S. journalist Evan Gershkovich until March 30, just over a year since his arrest on espionage charges.

The announcement was made in a closed hearing. Gershkovich and his employer, the Wall Street Journal, firmly deny all charges.

"It is chilling and outrageous that Evan has now spent 10 months of his life in prison, simply for doing his job," the newspaper said in a statement Friday.

"While these are clearly sham proceedings about patently false charges, we intend to appeal today's ruling, as we have in the past. Journalism is not a crime, and we continue to demand Evan's immediate release."

Gershkovich was detained during a reporting trip to the Russian city of Yekaterinburg. Russia's security service accuses him of collecting information about secret state activities at the direction of the U.S.

— Jenni Reid

Russia's defense industry to ramp up output this year

A spokesperson for Russia's Defense Ministry said the country's defense industry will sharply increase the supply of weapons and military equipment to its armed forces this year, news agency Interfax reported Friday.

Deputy Minister of Defense Alexey Krivoruchko said Russia's armed forces would receive more than 36,000 basic types of military equipment, 16.5 million weapons and over 1 million units of portable weapons, personal armor protection and communications equipment.

Krivoruchko said this is "several times higher" than the figures for 2023 and 2022.

"According to contracting has been carried out for these positions, the necessary budget funding has been allocated," he added.

— Sam Meredith

Kremlin 'not aware' of list identifying Ukrainian prisoners of war killed in plane crash

Kremlin spokesman Dmitry Peskov said Friday he was unaware that any official list identifying the Ukrainian prisoners of war killed in a military transport plane crash had been published.

At a press briefing on Friday, Peskov was asked whether he was aware of Ukraine's claim that some of the prisoners of war on board the plane, whose names were published by Russian media, had already been handed over to Ukraine in earlier prisoner swaps.

"No, I am not aware of this," Peskov replied. "I am also unaware that these lists have been officially published anywhere."

Russia and Ukraine have traded various accusations over the shooting down of a Russian military transport plane on Wednesday. It was carrying 65 Ukrainian prisoners of war and nine Russians.

— Sam Meredith

Hyundai finalises Russia exit as local firm buys its two car plants

Hyundai on Friday said it had signed a deal to sell its two Russian plants, making the South Korean firm the latest global carmaker to exit Russia since the Ukraine conflict began.

The Russian buyer, Art-Finance, said it had finalised the purchase of Hyundai's St. Petersburg plants on Jan. 24, and received approvals from the Russian government and federal anti-monopoly service.

Most European, Japanese and South Korean carmakers suspended production and left the Russian market after Moscow despatched troops to Ukraine in February 2022, often selling for a nominal fee as Russia has made it difficult to extract funds.

Hyundai Motor said in December it planned to sell its Russian assets for 10,000 roubles ($111.69), taking a 287 billion won ($214.7 million) loss.

— Reuters

NATO's Stoltenberg: Hungary will ratify Sweden's membership at end of February

NATO Secretary General Jens Stoltenberg said Friday that Hungary's parliament is expected to ratify Sweden's accession to the military alliance when it reconvenes at the end of February, Reuters reported.

Stoltenberg and Hungarian Prime Minister Viktor Orban spoke on the phone on Wednesday, with Orban telling the NATO boss that his government would support Sweden's membership.

Black boxes from crashed POW plane reach Moscow lab

The black boxes from the Russian military transport plane that was shot down near the Ukrainian border on Wednesday, killing 65 Ukrainian prisoners of war and nine Russians, have arrived at a Moscow laboratory to be analyzed, Russia's RIA news agency reported Friday.

U.S. aid to Ukraine hangs in the balance amid Trump border deal opposition

Bipartisan U.S. Senate negotiations over a border security deal that ties in aid for Ukraine have hit a critical juncture, Republican Senator John Thune told reporters on Thursday, according to Reuters.

The White House said last week that the U.S. money supply to Ukraine has now run out, which could leave Kyiv ill-equipped to repel the Russian invasion.

A small bipartisan group of senators is seeking a way to please Republicans aligned with Donald Trump, the front-runner for the party's presidential candidacy, who has openly pressured allies not to compromise on legislation that would help President Joe Biden in the run-up to November's election.

Biden and Senate Republican Leader Mitch McConnell have been hammering out a plan for months in the hope of convincing the Republican right to sign off on aid to Ukraine, but McConnell is reportedly wavering over the implications of Trump's opposition to a deal.

The former president said on his social media platform that any agreement would be "another Gift to the Radical Left Democrats" as Biden targets reelection.

— Elliot Smith

Zelenskyy: Ukraine has officially begun EU accession screening process

Ukraine formally started the screening process to begin talks over its future membership of the European Union on Thursday, President Volodymyr Zelenskyy said.

In a post on X, the Ukrainian leader said he welcomed the start of "substantial preparations for Ukraine's EU accession talks" in Brussels, following an agreement reached with EU Commission President Ursula von der Leyen last week at the World Economic Forum in Davos, Switzerland.

"The thorough work of assessing the conformity of Ukrainian legislation with EU norms, the formation of Ukraine's delegation, and our negotiating position are all ahead of us," Zelenskyy added.

"I expect full engagement of Ukrainian government team and the first intergovernmental conference to be held already this spring."

— Elliot Smith

Kyiv working to organise visit by Hungary's Orban, Ukraine deputy PM says

Ukraine is working to organise a visit by Hungarian Prime Minister Viktor Orban, Ukrainian Deputy Prime Minister Olha Stefanishyna said on Thursday, in remarks related to Reuters by her aide.

— Reuters

Russia says Ukraine had 15-minute warning on PoW flight, Kyiv denies this

A senior Russian lawmaker said Ukrainian military intelligence had been given a 15-minute warning before a Russian military transport plane carrying Ukrainian prisoners of war entered an area where it was shot down on Wednesday.

Ukraine denied the assertion by Andrei Kartopolov, a former general with close ties to Russia's defence ministry, and called for an international investigation.

Moscow accuses Kyiv of downing the Ilyushin Il-76 plane in Russia's Belgorod region, killing all 74 people on board, including 65 captured Ukrainian soldiers en route to be swapped for Russian POWs. Ukraine has neither confirmed nor denied that assertion, but challenged details of Moscow's account.

"The Ukrainian side was officially warned, and 15 minutes before the plane entered the zone they were given complete information, which they received and the Main Intelligence Directorate of the Ukrainian Armed Forces confirmed receipt of," Kartapolov told lawmakers, according to the ruling United Russia party.

"We all know very well what happened next," added Kartapolov, who heads Russia's parliamentary defence committee.

His assertion contradicted statements by Ukrainian military intelligence that Russia had not informed it about the flight arrangements.

Ukrainian military intelligence spokesperson Andriy Yusov, in comments to Reuters, reiterated on Thursday that - contrary to practice before previous PoW swaps - Kyiv had received no requests from Russia to refrain from attacks in the airspace where the plane was downed.

— Reuters

Russia prioritising military spending over public infrastructure

Recent heating breakdowns in 16 locations across Russia amid sub-freezing temperatures show that the country has routinely prioritized military spending over re-investment in general public infrastructure, the U.K.'s Ministry of Defence said Thursday.

Heating breakdowns have become commonplace in Russia this winter, particularly as regional governments have been asked to "take on the burden of operating with less federal revenue and ... to fund local volunteer forces which has likely stretched their budgets and necessitated some cuts to maintenance spending," the U.K. said on X, formally known as Twitter.

The mobilization of thousands of men to fight in Russia's armed forces has also likely led to a workforce shortage across all industries, including heating engineers and plumbers, the ministry noted in an intelligence update.

Noting that Russian President Vladimir Putin had asked the Minister of Emergency Situations Aleksandr Kurenkov to ensure the supply of heating and electricity to residents, the ministry said "appearing to tackle this issue is likely a key concern for Putin" ahead of presidential elections in March.

— Holly Ellyatt

Fragments of possible missile found at plane crash site, media reports

Fragments of what appears to be an anti-aircraft guided missile were found at the crash site of the downed Russian military transport plane, Russian new agency TASS reported Thursday.

"Elements of [what is] presumably anti-aircraft guided missile that hit the Il-76 were found at the crash site in the Belgorod region," TASS said, adding that the news agency had been informed of the development by the emergency services.

Military investigators and forensic scientists are searching for metal structures, TASS reported. Earlier, the planes black boxes were found. It's hoped that the flight data recorders will shed light on what happened to the Il-76 plane that crashed on Wednesday, killing all 65 Ukrainian prisoners of war and nine Russians on board.

Russia claimed Ukraine shot the plane down with several missiles. Ukraine has not admitted nor denied responsibility for the attack, calling for an international investigation into the incident.

CNBC was unable to confirm the information in the TASS report.

— Holly Ellyatt

Read CNBC's previous live coverage here:

Moscow and Kyiv face off over downed POW plane amid suspicion and allegations