Czech police are working to uncover the motive behind the country’s worst-ever mass shooting, which saw a student open fire at a university in central Prague, killing 14 and wounding 25 others.

Czech President Petr Pavel has appealed for unity and said the killings should not be used to launch political attacks or spread misinformation.

He expressed his “great sadness” and “helpless anger at the totally unnecessary” loss of life.

The shooting began at around 15:00 local time on Thursday at the Faculty of Arts building of Charles University in the centre of Prague. The gunman opened fire in the corridors and classrooms of the building, apparently killing at random, while staff and students used furniture to barricade themselves into rooms.