(Updates after meeting)
LONDON, Feb 20 (Reuters) - Britain's Foreign Office summoned Ukraine's ambassador to the UK on Thursday to discuss what it described as "shocking violence" in Kiev in which more than 50 people have been killed.
Fresh fighting broke out in central Kiev on Thursday, shattering a truce declared by Ukrainian President Viktor Yanukovich, as the Russian-backed leader met European ministers demanding he compromise with pro-EU opponents.
"(Minister for Europe David Lidington) expressed extreme concern over the reports of further violence and deaths, and made clear that action against peaceful protesters on Independence Square is unacceptable," the Foreign Office said in a statement after the meeting.
Commenting on reports that witnesses had seen snipers firing live ammunition during the clashes, Lidington told the BBC he had raised that with the ambassador, who had not been able to give a "definitive view".
"There should be a full and independent thorough investigation of those killings," Lidington said. "The people responsible for those shootings need to be held to account, wherever they come from."
Britain's Foreign Secretary William Hague is travelling to Brussels to meet with other EU foreign ministers on Thursday to discuss possible targeted sanctions against those deemed responsible for the bloodshed. (Reporting by Kylie MacLellan; Editing by Stephen Addison and Andrew Osborn)