ONDON/KIYV: Russia will face severe economic sanctions if it installs a puppet regime in Ukraine, a senior UK minister said on Sunday after Britain accused the Kremlin of seeking to install a pro-Russian leader there.

Britain made the accusation late on Saturday, also saying Russian intelligence officers had been in contact with a number of former Ukrainian politicians as part of plans for an invasion.

The Russian Foreign Ministry dismissed the comments as "disinformation", accusing Britain and NATO of "escalating tensions" over Ukraine.

Mykhailo Podolyak, a Ukrainian adviser to the presidential office, said the allegations should be taken seriously.

"There'll be very serious consequences if Russia takes this move to try and invade but also install a puppet regime," British Deputy Prime Minister Dominic Raab told Sky News on Sunday.

The British accusations, first made in a statement late on Saturday by the foreign ministry, come at a time of high tensions between Russia and the West over Russia's massing of troops near its border with Ukraine. Moscow has insisted it has no plans to invade.

The foreign ministry said it had information the Russian government was considering former Ukrainian lawmaker Yevhen Murayev as a potential candidate to head a pro-Russian leadership.

Murayev, is a pro-Russian politician who opposes Ukraine's integration with the West. According to a poll by the Razumkov’s Centre think tank conducted in December 2021, he was ranked seventh among candidates for the 2024 presidential election with 6.3% support.

Murayev poured cold water on Britain's claims that Russia wants to install him as Ukraine's leader, in comments to Britain's Observer newspaper. In a Facebook post later on Sunday, he called for an end to dividing Ukraine into pro-Western and pro-Russian politicians.

"The time of pro-Western and pro-Russian politicians in Ukraine is gone forever," he said. "Ukraine needs new politicians whose policy will be based solely on the principles of the national interests of Ukraine and the Ukrainian people."

The British foreign ministry declined to provide evidence to back its accusations. A ministry source said it was not usual practice to share intelligence matters, and the details had only been declassified after careful consideration to deter Russian aggression.

In a message to Reuters, Ukrainian adviser Podolyak acknowledged there was doubt among Ukrainians as to whether Murayev was "too ridiculous a figure" to be the Kremlin's pick to lead Ukraine. But he added that Russia had propped up previously minor figures in leadership positions in annexed Crimea and separatist-held Donbass.

Therefore "one should take this information as seriously as possible", he said.

Diplomatic Efforts

The British claims came after the top U.S. and Russian diplomats failed on Friday to make a major breakthrough in talks to resolve the crisis over Ukraine, although they agreed to keep talking.

Russia has made security demands on the United States including a halt to NATO's eastward expansion and a pledge that Ukraine will never be allowed to join the Western military alliance.

U.S. National Security Council spokesperson Emily Horne said in a statement: "This kind of plotting is deeply concerning. The Ukrainian people have the sovereign right to determine their own future, and we stand with our democratically-elected partners in Ukraine."

Britain, which this week supplied 2,000 missiles and a team of military trainers to Ukraine, also said it had information that Russian intelligence services were maintaining links with "numerous" former Ukrainian politicians, including senior figures with links to ex-President Viktor Yanukovich.

Yanukovich fled to Russia in 2014 after three months of protests against his rule and was sentenced in absentia to 13 years in jail on treason charges in 2019.