Ukraine’s Interior Ministry denied reports that police officers were defecting to the side of anti-government protesters.
Pro-West demonstrators hurled Molotov cocktails at riot police at Kiev's central Independence Square as violence ended a short-lived truce on Thursday.
At least one police officer was killed and 29 others wounded in the latest violence, officials said. At least ten other cops died in clashes earlier this week.
A statement from President Viktor Yanukovich's office accused the protesters of "using firearms, including sniper rifles."
It added: "They are shooting to kill."
However, the pro-West demonstrators alleged that police snipers had opened fire from buildings around Independence Square on Thursday.