A 25-year-old Ukrainian National Guard officer died on Monday after being shot in the heart in clashes between protesters and police outside parliament, officials said.

"He died on the operating table," a spokeswoman for the National Guard, Svitlana Pavlovska, told AFP. Interior ministry advisor Anton Gerashchenko said the victim was a 25-year-old conscript, adding that some of the protesters had used guns in addition to grenades.