Boris Johnson is weighing up sending fighter planes and the warships to eastern Europe as he warned Vladimir Putin against invading Ukraine.
The Prime Minister has said that the UK “will not flinch now” and will stand by fellow NATO countries in case of an attack by Russia who has been amassing troops and armaments on the border with Ukraine.
He said that he is considering sending RAF Typhoon fighters and Royal Navy warships to the region after sending 350 troops to Poland.
While he is also ready to ask parliament for sanctions on Russian individuals and companies if there was an invasion.
With Russia having amassed an estimated 130,000 trips near its border with Ukraine, Foreign Secretary Liz Truss is to head to Moscow for talks as diplomatic attempts to avert a war continue.
United States officials have said an attack by Russia on Ukraine could occur within days or weeks, while Russia has denied it is planning an invasion.
Putin has claimed that the West is using NATO to undermine Russia.
Johnson wrote in The Times : "If he launches another invasion, he will force the West to bring about much of what he seeks to prevent. In fact this is already happening.
"Because of his build-up, America, France, Italy and other allies are deploying forces to NATO's south-eastern flank, just as the UK reinforces the northeast.
"Nor could there be a more compelling argument for the necessity of NATO than the sight of Russian tanks invading a European country once again.
"So I hope the Kremlin might yet realise how its objectives would not be served by inflicting still greater destruction and bloodshed on Ukraine."
Earlier on Monday Defence Secretary Ben Wallace said the 350 British troops being dispatched to Poland will send a strong signal that the two countries "stand side by side".
Poland is also facing a crisis on its own border with Belarus, whose leader Alexander Lukashenko is an ally of Putin.
Wallace said the extra troops will add to 100 Royal Engineers already in Poland.
He denied that NATO is trying to use "divide and rule" tactics against Moscow.
"NATO is a defensive alliance. It poses no threat to Russia. It is a self-defence mechanism amongst our allies. That is what it is there for. No one wants to divide and rule Russia," he said.
Johnson has said that sanctions will be ready to be imposed should there be a Russian attack.
"British sanctions and other measures will be ready for any renewed Russian attack," Johnson wrote.
"The government will ask parliament for new powers to sanction a wider range of Russian individuals and entities, including any company linked to the Russian state or operating in a sector of strategic importance to the Kremlin."
The UK is also preparing to reinforce the British-led NATO battlegroup in Estonia, Johnson said.
"I welcome Germany's statement that Nord Stream 2 would be reconsidered in the event of an incursion," he added.
On Monday, S President Joe Biden said after meeting German Chancellor Olaf Scholz that the Nord Stream 2 gas pipeline would be halted if Russia invades Ukraine.
Scholz said the pair had the same approach to Ukraine, to Russia and to sanctions, but did not directly confirm the Nord Stream 2 plans.
Europe's most divisive energy project, Nord Stream 2 is designed to double the amount of gas flowing from Russia straight to Germany, bypassing Ukraine.
