The fragile truce in Ukraine, brokered just yesterday, was shattered Thursday by a barrage of Molotov cocktails and gunfire as protesters advanced on police lines in the capital of Kiev.
Government forces fired on activists, killing at least 70 people and wounding hundreds of others.
Protesters tried to protect themselves with shields, while teams of demonstrators carried bodies away on sheets of plastic or planks of wood.
Protesters, in turn, took dozens of riot police hostage.
"This is what they mean by truce. We don't trust them!" one activist said.
Meanwhile, a hotel lobby became a hospital and a morgue for the wounded and the dead.
"It is horrible," one doctor said. "It is hard to understand how in 21st century people could be just shooted [sic] directly someone."
Anti-government protesters, angry at their president's embrace of Russia, have occupied Independence Square for months.
On Thursday, protest leader Viltaly Klitschko, a former boxing champ, issued an urgent appeal for peace and demanded that President Viktor Yanukovych schedule early elections.
As European ministers scrambled to negotiate a resolution, U.S. Ambassador to Ukraine Geoffrey Paytt warned against more violence.
"We believe Ukraine's crisis can still be solved via dialogue, but those on both sides who fuel violence will open themselves to sanctions," Pyatt tweeted.
In the meantime, thousands of anti-government activists are still occupying Independence Square and many more are arriving. The situation could mean even more violence and death.