British Prime Minister Boris Johnson will speak to Russian President Vladimir Putin this week, urging him to step back from escalating tensions over Ukraine, Downing Street said Friday.
Johnson "will reiterate the need for Russia to step back and engage diplomatically when he speaks to President Putin this week," a Downing Street spokeswoman said, without specifying which day this will take place.
The British prime minister is "determined to accelerate diplomatic efforts and ramp up deterrence to avoid bloodshed in Europe", Downing Street said.
Johnson is to visit the region in the coming days.
Relations between Russia and the West are at their lowest point since the Cold War after Moscow deployed tens of thousands of troops on the border of Ukraine.
The UK's foreign ministry is expected to announce toughening its sanctions regime on Russia in parliament on Monday, to target strategic and financial interests.
This comes as a senior Conservative lawmaker warned Friday that dirty Russian money flooding into London threatens national security.
"The money hidden in accounts and properties is used to undermine the security of the UK and the British people," Tom Tugendhat, who chairs parliament's influential Foreign Affairs Select Committee, wrote in a newspaper.
Johnson warned this week that Russia faces Western sanctions "heavier than anything" seen before if it invades Ukraine.
The prime minister said that Moscow risked sparking a prolonged conflict that would be a "new Chechnya".
Johnson took part in crisis talks with US President Joe Biden and other European leaders on Monday.
The United Nations Security Council, which includes the UK, will hold a public meeting on the Ukraine crisis on Monday.