Ukrainian President Viktor Yanukovych has warned that the country's stability is threatened by continuing clashes between police and anti-government protesters in the capital Kiev.
A burnt-out line of buses and trucks in central Kiev marks the boundary between protesters and police.
Clashes erupted on Sunday, after many more demonstrators rallied peacefully against President Viktor Yanukovych.
The authorities say police have the right to use firearms in self-defence.
In a statement on Monday evening, President Yanukovych said that "now, when peaceful actions are turning into mass unrest, accompanied by riots and arson attacks, the use of violence, I am convinced that such phenomena are a threat not only to Kiev but to the whole of Ukraine".