Barack Obama urges NATO to stand against Russia

US President Barack Obama has urged leaders of the NATO military alliance to stand firm against Russia over its “seizure” of the Crimean peninsula from Ukraine.

Obama made the comments on Friday at a NATO summit in Warsaw, Poland, his last NATO summit before he leaves the White House in January.

Ties between the West and Russia have been in tatters since the Crimean Peninsula joined Russia in a referendum in March 2014.

Ukraine has also been carrying out a military crackdown on pro-Russian forces fighting for greater autonomy in the eastern part of the country.

"In Warsaw, we must reaffirm our determination — our duty under Article 5 of the North Atlantic Treaty — to defend every NATO ally," Obama said.

"We need to bolster the defence of our allies in central and eastern Europe, strengthen deterrence and boost our resilience against new threats, including cyber attacks."

Obama also told NATO leaders that Britain's vote to leave the European Union (EU) should not weaken the Western military alliance.

The US president said America's "special relationship" with the UK would survive the EU referendum decision he had previously warned against.

"The special relationship between the US and the UK will endure. I have no doubt that the UK will remain one of NATO’s most capable members," he said.

However, Obama acknowledged that the UK vote raised significant questions about the future of EU integration.

The 28-nation NATO will formally agree to deploy four battalions totaling 3,000 to 4,000 troops in the Baltic states and Poland on a rotating basis to reassure eastern members of its readiness to defend them against any Russian aggression.

Moscow said it was meaningless for the US-led military alliance to describe Russia as a threat and it hoped "common sense" would prevail at the NATO summit.

“Moscow was and remains open to dialogue with NATO and is ready to cooperate with it,” Kremlin spokesman Dmitry Peskov said Friday in a conference call with journalists.