The US has raised the possibility of military intervention in the Ukraine crisis even as diplomatic efforts to resolve the standoff between Russia and the West showed some shaky signs of progress.

General Martin Dempsey, Chairman of the Joint Chiefs of Staff, said Russia’s interference in Ukraine “exposes Eastern Europe to some significant risk” and the US “wound respond” if its allies are threatened.

In an interview with PBS, Gen. Dempsey did not rule out the possibility of US military intervening in the Ukraine crisis.

“That's a question that I think deserves to be assessed and reassessed and refreshed as this thing evolves.”

The Pentagon has sent a missile warship to the Black Sea and additional fighter jets to Poland and Lithuania to “reassure” its allies in Europe.

“Remember, we do have treaty obligations with our NATO allies. And I have assured them that if that treaty obligation is triggered, we would respond,” the US military chief said.

US President Barack Obama on Saturday called the leaders of the three ex-Soviet Baltic states - Latvia, Estonia and Lithuania, to reaffirm the US “unwavering commitment to our collective defence commitments under the North Atlantic Treaty” in connection with Russia’s moves in Ukraine, the White House said.

Meanwhile, intensive diplomatic exchanges focused on involving international organisations in efforts to ease tensions over Ukraine. Hours after the Russian and German Foreign Ministers discussed on telephone on Sunday “possibilities for extending international assistance to normalisation” in Ukraine, Russian President Vladimir Putin “exchanged views on possible international efforts to settle the crisis” with British Prime Minister David Cameron and German Chancellor Angela Merkel, according to the Kremlin.

“Despite persisting differences” in their views on the Ukrainian developments, the leaders expressed “shared interest in de-escalation of tensions and early normalisation of the situation,” the Kremlin said.

Ukraine’s Acting Foreign Minister Andriy Deshchytsia was quoted as saying that “some small steps” forward had been made in efforts to establish a contact group of Ukraine, Russia and some western countries.

More In: World | International | News