The United States called on Ukraine's rival political forces to respect the rule of law and urged that disputes be resolved nonviolently.
In a statement, U.S. State Department spokesman Sean McCormack said the United States is asking all Ukrainian political leaders to take full responsibility for the actions of their supporters.
Christiane Hohmann, the European Commission's spokeswoman for external relations, told RFE/RL from Brussels that the EU hopes for a political settlement of the standoff.
"We call upon all political forces concerned to cooperate and find a peaceful way to defuse the current political situation," she said.
Russia's Foreign Ministry also voiced concern and urged a compromise between pro-Western and pro-Russian factions.
"As for the possibility of Russia, or the CIS, or other countries getting involved in helping resolve this crisis, I believe it is up to the Ukrainian side, first and foremost," Russian Foreign Minister Sergei Lavrov told journalists in Yerevan today. "If Ukraine asks for assistance, let me assure you that Russia will not hesitate to provide such help."
(with material from agency reports)