The United Kingdom has offered to deploy land, air, and sea forces to bolster NATO countries' capabilities on their northern and eastern borders, in a bid to take part in the mounting war threats directed at Russia.

Boris Johnson is expected to meet Russian President Vladimir Putin this week, despite intense domestic pressure over a possible leadership challenge in the aftermath of the "partygate" scandal.

Johnson said the additional resources demonstrated Britain's commitment to its Nordic and Baltic allies, and they come after US President Joe Biden promised on Friday to send a number of  US troops to eastern Europe and NATO countries "in the near term."

He said in a statement that the decision was made to "send a clear message to the Kremlin."

"We will not tolerate their destabilizing activity, and in the face of Russian hostility, we will always stand with our NATO allies."

The deployments included sending two warships to the Black Sea, increasing troop numbers and supplying rocket systems in Estonia, near the Russian border, and deploying fast jets from a base in Cyprus to patrol Romanian and Bulgarian airspace.

UK officials head to Brussels

Officials from the UK will travel to Brussels this week to finalize the details of the military assistance. Johnson directed his "defense and security" chiefs to step up their efforts in Europe, and he sent his foreign and defense secretaries to Moscow to meet with their Russian counterparts.

Moreover, Tony Radakin, the UK's chief of defense staff, will brief the cabinet on what has been dubbed the Ukrainian crisis on Tuesday.

On Friday, top US officials urged diplomacy, claiming that Russia now has enough troops and equipment to threaten Ukraine as a whole. 

Both the US and the UK have withdrawn their staff and families from their embassies in Kyiv, and British travel advisories now advise against all but necessary travel to the country.

On another note, the Foreign Office is expected to announce tougher sanctions on Monday, allowing the UK to target Russia's strategic and financial interests.

Impact of US threats on Ukraine

Biden has previously stated that he believes Russian President Vladimir Putin will "move in" to Ukraine, and White House press secretary Jen Psaki stated that "an invasion could come at any time."

The Ukrainian government, concerned about the impact of such statements on the economy and public morale, has maintained that the threat of an invasion is real, but not any more so than in previous months.

On that note, 8,500 US troops have been placed on "heightened preparedness to deploy" to assist NATO if necessary, the Pentagon stated earlier. 

Russia has repeatedly denied the Western allegations of intending to invade Ukraine, and Moscow's Foreign Intelligence Service accused the US State Department of spreading false information about the alleged troop buildup.