Nato has agreed to bolster air, land and sea forces on it Eastern flank near Russia and Ukraine.

Nato Secretary-General Jens Stoltenberg said: "We now have war in Europe on a scale and of a type we thought belonged to history. This is a grave moment for the security of Europe."

Stoltenberg has condemned the Russian invasion of Ukraine as a “blatant violation” of international law.

Speaking at Nato headquarters in Brussels, Mr Stoltenberg said he was calling a virtual summit of alliance leaders on Friday to discuss the “serious threat” to security in the region.

“This is a grave moment of the security of Europe. Russia’s unprovoked and unjustified attack on Ukraine is putting countless lives at risk,” he said.

“This is a deliberate, cold-blooded and long-planned invasion.

“It is a blatant violation of international law, an act of aggression against a sovereign, independent and peaceful country and a serious threat to Euro-Atlantic security.”