Russia is said to be moving nuclear-capable weapons near Nato borders as part of military exercises as the country embarks on a surprise large-scale drill across its fleets.

Sophisticated Tupolev 22-M3 bombers are being mobilised in Crimea, the former Ukrainian region which later annexed to Russia, while missiles are being positioned in Kaliningrad region.

The Iskander missiles deployed in Kaliningrad region, which borders Poland and Lithuania, have a target range of about 500kms and several Nato members fall under the periphery.

The latest deployment being conducted across Russia's several military units involve around 40,000 troops. Russian President Vladimir Putin has ordered the drills in a surprise show of strength, when tensions with the Western world are at its worst.

Poland has said the Moscow's latest move is a veiled threat to the Nato states in order to put pressure on the alliance to tread soft on Russia, while discussing economic sanctions later this week.

"I'm certain that Russia is making these kinds of gestures … in order to influence a little the decision of the European Council, which relates to extending sanctions, or, eventually, if there's no peaceful solution and no respect of Minsk 2 [a ceasefire accord], imposing more painful economic sanctions," Polish Prime Minister Ewa Kopacz told reporters.

Following Putin's order to put the Northern Fleet in full combat readiness in preparation for the military manoeuvres, several other Russian regions have been asked to follow suit.

Russian defence ministry, nevertheless, defended its move saying that all military activities adhere to international regulations.

"The number of servicemen and military hardware involved in the exercises does not exceed the levels falling under the 2011 Vienna Document and requiring timely notification," Moscow's defence minister Anatoly Antonov said and added that Nato members have been informed via necessary channels about the drills.