Raids have also been carried out at Ukraine’s tax office, targeting top tax and customs officials, and on the home of an influential former interior minister.

It comes two days before Kyiv hosts a summit with the European Union at which it wants to show western allies it is cracking down after years of chronic corruption.

The government sees Friday’s summit as key to its hopes of one day joining the bloc.

In a political shake-up, more than a dozen officials quit or were sacked last week.

Former interior minister Arsen Avakov told Ukrainian media that investigators also searched his house following a helicopter crash last month in which his successor, Denys Monastyrsky, died.

Mr Avakov quit in 2021 after a scandal-ridden tenure.

Ukraine’s police and security services say they have uncovered a scheme to embezzle more than $1bn at oil producer Ukrnafta and oil refinery Ukrtatnafta, companies that billionaire Ihor Kolomoisky used to partly own.

In a fresh wave of high-profile anti-corruption raids, officials raided the powerful oligarch’s home, as well as those of other incumbent and former top officials.

Kolomoisky, who could not be reached for comment, has previously denied any wrongdoing.

A Royal Air Force chief has suggested the UK’s refusal to provide Ukraine with fighter jets could change.

Air Chief Marshal Sir Mike Wigston told the Commons Defence Committee: “I think the Prime Minister and the Secretary of State yesterday were very clear on where we stand on fast jets at this stage.

“But these are things that, the course of the invasion – of the brutal invasion and Ukraine’s heroic defence and how we have supported them – that has been an evolutionary process and I look to the future and we should be ready for any outcomes.”

He declined to say what air power the RAF could make available to Ukraine.

US president Joe Biden said on Monday he would not send warplanes to Kyiv.

The US has imposed sanctions on a Russian arms dealer, his son, a group of front companies across Asia, Europe and the Middle East and their leadership, in an effort to curb Russia’s access to weapons:

Ukrainian state security officials have searched the home of billionaire businessman Ihor Kolomoisky, in what is reported to be an investigation into possible financial crimes.

A senior governing party official confirmed Kolomoisky’s home had been searched – as well as that of a former interior minister – but did not state the reason for the search.

Photographs circulating on social media appeared to show Kolomoisky, dressed in a sweatsuit, looking on in the presence of at least one SBU officer inside a large wooden home. Reuters could not immediately verify the authenticity of the images.

Kolomoisky is one of Ukraine‘s richest men and a one-time ally of Volodymyr Zelensky, who launched a crackdown on wealthy businessmen known as “oligarchs” in late 2021 – before Russia launched its full-scale invasion.

Kolomoisky, who is from the central city of Dnipro and owns an array of assets including one of Ukraine’s most influential television channels, backed Zelenskiy’s election campaign in 2019.

Latvia has threatened to boycott next year’s Paris Olympics if Russian athletes are allowed to take part during the war in Ukraine and is calling on other countries to form a coalition to pressure international sports bodies:

Vladimir Putin has said Russia’s military must stop the shelling of Russian regions from Ukrainian territory, which he said had left many people homeless or without power.

Mr Putin was addressing a government meeting about restoring destroyed housing and infrastructure in regions of southwest Russia that border Ukraine.

“Of course, the priority task is to eliminate the very possibility of shelling. But this is the business of the military department,” he said in remarks published on the Kremlin website.

Ukraine does not claim responsibility for strikes in Russian territory but has described them as “karma” for Moscow’s invasion, which has razed Ukrainian cities and systematically targeted the country’s energy infrastructure, leaving people frequently without power and water in the depths of winter.

Putin cited the Russian regions of Belgorod, Bryansk and Kursk, as well as Crimea, which Russia seized from Ukraine and annexed in 2014, as areas where housing had been damaged or destroyed.

People were facing “very acute” problems, and repairs and compensation were needed, he said.

“Many people found themselves in a difficult situation, lost their homes, were forced to move to relatives or to temporary places of residence, faced interruptions in the supply of water, heat, and electricity,” he said.

A Kremlin-backed regional leader in Donetsk claims the eastern Ukrainian city of Bakhmut has been surrounded by Russian forces, Reuters news agency reported.

“Bakhmut is now operationally surrounded, our forces are closing the ring around the city,” said Yan Gagin, an aide to Denis Pushilin — the Russia-backed leader of the illegally annexed Donetsk region.

Gagin claimed that fighting was now taking place for control of the Chasiv-Yar-Bakhmut highway.

Ukraine’s military leadership said there had been no let-up with Russian offensive operations, but spoke of heavy losses Russian forces were incurring in their battle for the town.

Downing Street has again ruled out supplying Ukraine with British fighter jets, despite Boris Johnson’s backing the idea.

Asked about the former prime minister’s attacks on the government for not sending jets, Rishi Sunak’s official spokesman said: “The Prime Minister welcomes all colleagues’ backing for Ukraine and is pleased the former prime minister is continuing his staunch support of the United Kingdom’s efforts to help Ukraine secure a lasting peace.”

But he said that Mr Johnson was “acting in his own capacity and not on behalf of the UK Government”.

The official said: “It’s currently not practical to send UK jets: we will continue to work closely with the Ukrainians to understand their needs and how allies can further support them.

“Given the complexity of UK fighter jets and the length of time required to train them we do not currently think it is practical to do so.”

Troops are fighting building to building in Bakhmut for gains of barely 100 metres a night, and the city was coming under constant Russian shelling, according to Ukrainian battleground reports.

Bakhmut came under renewed fire, as did the villages of Klishchiivka and Kurdyumivka on its southern approaches, the General Staff of the Ukrainian Armed Forces said late last night.

Russian forces also tried to advance on Avdiivka, the second focal point of Russian attacks in Donetsk region and Lyman, a town further north that was recaptured by Ukrainian forces in October, the military said. Further west, Russia fired on Vuhledar and a half dozen other towns and villages, it said.