Ukraine: Russia has deployed 6,000 troops, Kiev on high alert

Ukraine's defence minister says Russia has brought 6,000 extra troops into the country recently.

He claims Kiev is on the highest military alert following what he calls an "invasion".

The United States President Barack Obama has weighed in on the crisis.

He has warned Moscow there will be "costs" for any military intervention in the Crimean region.

President Obama has warned Moscow “there will be costs” if Russia intervenes militarily in crisis-torn Ukraine.

The US president’s blunt message came after armed men described as Russian troops took control of key airports in Crimea yesterday and Russian transport planes were said to have flown into the strategic region – an ominous sign of the Kremlin’s iron hand in Ukraine.

Mr Obama did not say what the “costs” might be, but US officials said he may cancel plans to attend an international summit in Russia this year and could halt discussions on deepening trade ties with Moscow.

The sudden arrival of men in military uniforms patrolling key strategic sites prompted Ukraine to accuse Russia of a “military invasion and occupation” – a claim that brought an alarming new dimension to the crisis.

In a hastily-arranged statement delivered from the White House, Mr Obama said: “Any violation of Ukraine’s sovereignty and territorial integrity would be deeply destabilising.”

Such action by Russia would not serve the interests of the Ukrainian people, Russia or Europe, Mr Obama said, and would represent a “profound interference” in matters that must be decided by the Ukrainian people.

“The United States will stand with the international community in affirming that there will be costs for any military intervention in Ukraine,” he added.

Earlier, Ukraine’s fugitive president resurfaced in Russia to deliver a defiant condemnation of what he called a “bandit coup”.

Appearing for the first time since fleeing the country last week, Viktor Yanukovych struck a tone both of bluster and caution – vowing to “keep fighting for the future of Ukraine,” while ruling out seeking Russian military help.

“Any military action in this situation is unacceptable,” he told reporters in the southern city of Rostov-on-Don, near the border with Ukraine.