Investigators on Friday were working to establish a motive for a deadly gun rampage in the center of Prague a day earlier, the Czech Republic’s worst mass shooting since the immediate aftermath of World War II.

The gunfire that erupted on Thursday at Charles University turned the historic center of one of Europe’s most serene cities into a scene of carnage, its festive Christmas mood marred by screams and the din of sirens. Tourists ran for safety while some students barricaded themselves inside classrooms. Others climbed out of windows, hiding on the ledge of a building.

The gunman killed 14 people and wounded 25 others, according to a revised official death toll released on Friday. The gunman, a 24-year-old student, fatally shot himself after the police surrounded him on the rooftop of the building, the authorities told a news conference on Friday.

The Czech Republic canceled soccer and hockey matches — usually immovable features of the pre-Christmas calendar — and declared Saturday a day of national mourning.