Ukraine's prime minister Mykola Azarov is warning anti-government protesters that authorities may use force.
Mr. Azarov told Russia's Vesti 24 television Tuesday that if those he calls "provocateurs" do not stop inciting clashes, officials will have no other choice.
He said he hopes common sense will prevail and that many issues can be resolved at the negotiating table.
Anti-government protesters marched through Kyiv for a third straight day Tuesday. Fighting between police and demonstrators has injured hundreds.
Ukrainians are angry at President Viktor Yanukovych's decision in November to back out of a plan to sign a trade deal with the European Union in favor of close ties with Russia.
The marchers are also upset over new laws restricting protests.
Mr. Yanukovych has offered to meet with opposition leaders.
Russian Foreign Minister Sergei Lavrov says the situation in Ukraine is "spinning out of control." Lavrov said Tuesday that Russia is doing everything it can to help "stabilize the situation" without meddling in Ukrainian domestic affairs.
In Washington, the U.S. Broadcasting Board of Governors expressed outrage for the bloody police attacks on dozens of journalists in Kyiv, including RFE/RL reporter Dmytro Barkar and cameraman Ihor Iskhakov. They were covering the protests on Monday when they were beaten and struck on the head by members of the elite Berkut police force.
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Sergei Lavrov, Russian Foreign Minister
"There are pogroms now, attacks against police, arsons, Molotov cocktails, explosive devices. This is scary. This is a total violation of any European norms."