Ukraine has ruled taking military action to prevent the secession of Crimea as prime minister Arseniy Yatsenyuk prepares to meet Barack Obama at the White House.
Ukraine's interim president Oleksandr Turchynov said that intervening in the southern peninsula, which is de facto controlled by Russian troops, would play into the hands of the Kremlin providing it with a pretext to deploy troops also in eastern Ukraine.
"We cannot launch a military operation in Crimea, as we would expose the eastern border and Ukraine would not be protected," Oleksandr Turchynov told AFP.
"They're provoking us to have a pretext to intervene on the Ukrainian mainland ... [but] we cannot follow the scenario written by the Kremlin."
Turchynov said Russia is refusing to seat at the diplomatic table with Ukraine's post-revolution authorities, claiming they are illegitimate.
Meanwhile the country' new Prime Minister Arseniy Yatsenyuk was flying to Washington in a diplomatic stunt to show Kiev has a strong backing in the West.
White House spokesman Jay Carney said Yatsenyuk's visit was meant to signal "that we strongly support Ukraine, the Ukrainian people and the legitimacy of the new Ukrainian government."
Yatsenyuk has called on the US and the EU for support against Russia, which he described as a country "armed to the teeth and that has nuclear weapons."
NATO has deployed two surveillance planes in Ukraine's western neighbours Poland and Romania, while the Ukrainian army has been placed in maximum operational readiness.
Yatsenyuk was voted as head of the government after former president Viktor Yanukovich fled amid mass street protests.
Earlier this week, Yanukovich spoke from his refuge in Russia's southern city of Rostov-on-Don and vowed to come back, claiming he was still in charge of Ukraine and its military.
He blamed post-revolution authorities for the imminent secession of the Crimean peninsula.
The regional parliament has declared independence from Ukraine ahead of a referendum on whether voters want to secede from Kiev and join Russia instead.
Crimean authorities are also working to form an independent army. Numerous pro-Russian volunteer soldiers swore an oath of allegiance in the semi-autonomous region in front of the regional leader Sergei Aksyonov.