Russia expels US deputy chief of mission Bart Gorman in Moscow

US and Russia are indulged in an intense diplomatic row over Ukraine crisis. (Representational)

A US Embassy spokesman told a Russian news agency on Thursday that Russia has expelled the deputy chief of of the US mission in Moscow. No details were given of why Bart Gorman was expelled. The State Department confirmed the expulsion, calling it unprovoked.

The move comes amid heightened tensions between Russia and the US, fuelled by fears that Moscow plans to invade Ukraine.

Spokesman Jason Rebholz told the state RIA Novosti news agency that Gorman was second in command in the US Embassy in Moscow and had an open visa. He spent less than three years in Moscow, the report said.

Tensions also spiked Thursday along the line that separates Ukrainian forces from Russia-backed separatists in the country's east, with the parties accusing each other of intensive shelling. Western fears resurged that Russia is planning to invade Ukraine, after weeks of East-West tensions that have threatened

Europe's post-Cold War balance of power.

The US and its NATO partners said they had seen no sign yet of Russia's promised troop withdrawal.

"We've seen some of those troops inch closer to that border. We see them fly in more combat and support aircraft," US Defense Secretary Lloyd Austin said at NATO headquarters in Brussels.

We see them sharpen their readiness in the Black Sea. We even see them stocking up their blood supplies. You don't do these sort of things for no reason, and you certainly don't do them if you're getting ready to pack up and go home.?

Russia held out an offer of diplomacy, handing the US a response on Thursday to offers to engage in talks on limiting missile deployments in Europe, restrictions on military drills and other confidence-building measures.

As US Secretary of State Antony Blinken headed to New York for the UN Security Council meeting and then Germany for the Munich Security Conference, Russia delivered its long-awaited responses to US proposals on Ukraine and broader European security. A senior State Department official said the Russians had presented its response to US Ambassador to Russia John Sullivan in Moscow.