Anti-government protesters are again clashing with police in Ukraine's capital Kiev, despite a truce agreed between President Viktor Yanukovych and opposition leaders.
Some live rounds have been fired on Thursday, but it is not clear by whom. Protesters are throwing petrol bombs, while police are using water cannon. The health ministry says the death toll in protests this week has risen to 28.
Fires burned at the main protest camp, the Maidan, through the night. Two armoured vehicles have been seen in the street leading towards the square.
Most of the victims died during clashes on Tuesday - the bloodiest day since the unrest erupted in late November last year.
Earlier, a statement on the presidential website said they had agreed to start "negotiations" aimed at ending the bloodshed of the past two days in Kiev. They also agreed to try to stabilise "the situation in the state in the interests of social peace".
The United States has been urging the Ukrainian government to pull back riot police from Independence Square in Kiev, call a truce and hold discussions with the opposition.
The president sacked the head of the armed forces on Wednesday. No reason was given for the dismissal of Volodymyr Zamana, who was replaced by the commander of Ukraine's navy, Yuriy Ilyin, but earlier the Defence Ministry had announced the armed forces might be deployed in a nationwide anti-terrorist operation.
Meanwhile, Europe's leaders are to consider urgent sanctions against Ukraine. An emergency European Union meeting has been called for Thursday and the foreign ministers of France, Germany and Poland are travelling to Kiev before then to assess the situation.
Yanukovych 'solely responsible'
Swedish foreign minister Carl Bildt has condemned the violence, saying Mr Yanukovich has blood on his hands.
"He is the single person who could have prevented this by opening up for an inclusive and democratic dialogue with opposition," Mr Bildt says. "Instead he has gone for a policy of confrontation and repression. He's the single individual responsible for the deaths and the catastrophe of Ukraine."
United States President Barack Obama has warned Ukraine to ensure the military does not step into issues he says can be resolved by civilians.
Mr Obama says the US and its European allies will be watching the situation closely and there will be consequences if, as he puts it, people step over the line.