A student opened fire Thursday at a university in Prague, killing at least 14 people, officials said, and injuring more than 20 in the Czech Republic’s worst mass shooting.

The bloodshed took place in the philosophy department building of Charles University, where the shooter was a student, Prague Police Chief Martin Vondrasek said. The gunman also died, authorities said. His name has not been released.

Vondrasek said in the evening that 14 people had died and 25 were injured, after earlier reporting that 15 had died and 24 were hurt. He didn’t explain the change. Authorities warned that the death toll could rise.