New Delhi, Feb 20 (IANS): UK Foreign Secretary Liz Truss has warned that Russian President Vladimir Putin will keep waging war on neighbouring countries if he is allowed to invade Ukraine, the Daily Mail reported.

As the Russian President put on a huge show of military strength with nuclear drills involving ballistic missiles, submarines and tank convoys on Saturday, Truss issued a last-ditch plea for the international community to unite to face down Moscow's aggression.

Truss used an exclusive interview with The Mail on Sunday to argue that if Putin attacked Ukraine it would be a precursor to Russia using force to annex more former Soviet states.

"We need to stop Putin because he will not stop at Ukraine.He's been very clear – his ambition doesn't just lead to him taking control of Ukraine, he wants to turn the clock back to the mid 1990s or even before then," she said.

"The Baltic States are at risk... the Western Balkans as well.

"Putin has said all this publicly, that he wants to create the Greater Russia, that he wants to go back to the situation as it was before where Russia had control over huge swathes of Eastern Europe.

"So it's so important that we and our allies stand up to Putin. It could be Ukraine next week but then which country will it be next?" she added.

The Foreign Secretary's comments came as UK Prime Minister Boris Johnson warned that a Russian invasion of Ukraine could cause "the destruction of a democratic state" and "the shock will echo around the world", the Daily Mail reported.

Speaking at the Munich Security Conference, the Prime Minister said the "omens are grim" from Russia on the possibility of an invasion in the coming days, and that the world could not "underestimate the gravity of this moment".