Violence is picking up in Ukraine, with at least 25 people dead and 200 injured following a battle between anti-government protesters and police in Kiev's Independence Square.
Protesters don't approve of Ukraine's pro-Russian president, Viktor Yanukovych. They are demanding democratic reforms and closer ties with Europe and the United States.
Yanukovych said the leaders of the opposition "crossed a line" by not condemning the violence, as the White House asks the same of Ukraine's president.
"We urge President Yanukovych to de-escalate immediately the situation and end the confrontation at Maidan," White House press secretary Jay Carney said. "We also urge him to re-start a dialogue with opposition leaders today to develop a consensus way forward for Ukraine."
Government forces have been tearing down the opposition's tent cities, which have been erected in parts of Kiev for nearly 3 months.