Vladimir Putin has deployed 50,000 Russian and North Korean troops in an attempt to recapture Kursk from Ukraine before Donald Trump takes office as US president in January.

Ukraine’s top military commander said “tens of thousands of enemy soldiers” had arrived to expel Kyiv’s forces from the Russian enclave, fuelling Western fears of a significant escalation of the war.

Nato allies believe Putin is hoping to recapture territory lost to Ukraine before Mr Trump’s inauguration on Jan 20.

A British defence intelligence assessment seen by The Telegraph shows Russia is likely to ramp up kamikaze drone attacks on Ukrainian positions in the coming days, using new launch sites close to the border.

It was reported that Mr Trump used a phone call with Putin after the presidential election last week to warn the Russian leader against escalating the war, amid fears of a winter offensive boosted by North Korean troops and supplies.