At a conference in Munich where Western diplomats met leaders of the Ukrainian opposition, United States Secretary of State John Kerry said protesters believe "their futures do not have to lie with one country alone, and certainly not coerced".
"Nowhere is the fight for a democratic, European future more important today than in Ukraine," he said. "The United States and EU stand with the people of Ukraine in that fight."
But Russian foreign minister Sergei Lavrov, outnumbered in Munich by supporters of Ukraine's overtures to the European Union that President Viktor Yanukovich suddenly ditched last November, hit back with the same charge.
Lavrov said "political choice was preordained for Ukraine" when Nato offered Kiev potential membership of the western military alliance in 2008. Ukraine demurred but does cooperate with Nato on international peace missions such as that in Afghanistan.
"Here a choice is being imposed," said Lavrov, accusing some EU politicians of encouraging anti-Yanukovich protesters who "seize and hold government buildings, attack the police and use racist and anti-Semitic and Nazi slogans".
They traded barbs at the annual Munich Security Conference. Differences between the West and Russia on Ukraine and Syria, where Moscow backs President Bashar al Assad, made for a chilly atmosphere.
On the sidelines, Arseniy Yatsenyuk, an ally of jailed former prime minister Yulia Tymoshenko; Ukrainian boxer-turned-politician Vitaly Klitschko; lawmaker Petro Poroshenko and pop star Ruslana Lyzhychko lobbied for the opposition.
They led a small protest in the streets of the Bavarian capital amid meetings with Kerry, German Foreign Minister Frank-Walter Steinmeier and EU foreign policy chief Catherine Ashton.
"We expect support for Ukraine, support for a democratically peaceful movement, because everyone wants to see Ukraine as a modern European country," Klitschko told reporters.
Demonstrators were saying "enough, enough waiting, enough corruption, enough of living without rules", he said.