A lone gunman opened fire in a university building in central Prague, killing at least 14 people 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 killer was a student, Prague Police Chief Martin Vondrasek said.

The suspected gunman also died. His name has not been released.

Mr Vondrasek said 25 people were injured and authorities warned that the death toll could rise.

Police gave no details about the victims or a possible motive for the shooting at the building near the Vltava River in Jan Palach Square. Interior Minister Vit Rakusan said investigators do not suspect a link to any extremist ideology or groups.

Mr Vondrasek said police believe the suspect killed his father in his home town of Hostoun, just west of Prague, earlier in the day, and that he had also been planning to kill himself.

Later on Thursday, Mr Vondrasek said that, based on a search of his home, the gunman was also suspected of killing another man and his two-month-old daughter on December 15 in the east of Prague.

The police chief described the suspect as an excellent student but did not provide any other information.

The suspect suffered “devastating injuries” but it was not clear if he killed himself or was shot dead in an exchange of gunfire with officers, Mr Vondrasek said, adding that there was “nothing to suggest that he had an accomplice”.

The suspect legally owned several guns, and what he did was “well thought out, a horrible act”, Mr Vondrasek said.

“We mourn the loss of life of members of our university community, express our deepest condolences to all the bereaved and our thoughts are with all those affected by the tragedy,” Charles University said in a statement.

University authorities said they would tighten security in buildings with immediate effect.

The building where the shooting took place is located near the Vltava River in Jan Palach Square, a busy tourist area in Prague’s Old Town.

It is just a few minutes’ walk from the picturesque Old Town Square, a major tourist attraction where thousands of visitors have been enjoying a popular Christmas market.

The government quickly sought to quell concerns that the massacre was backed by foreign interests.

“There’s no indication that it has anything to do with international terrorism,” Mr Rakusan said.

“It’s a horrible crime, something the Czech Republic has never experienced,” he said.

Pavel Nedoma, the director of the nearby Rudolfinum Gallery, said he watched from a window as a person standing on a balcony of the building fired a gun.

Authorities evacuated everyone from the building and police said they were still searching the area, including the balcony, for explosives.

The building forms part of the square and faces a bridge across the river with a view of Prague Castle, the seat of the Czech presidency.

President Petr Pavel said he was “shocked” by what happened and offered his condolences to the relatives of the victims.

Where tourists, students and others would normally be enjoying the view of the iconic monument, chaos and terror instead took hold. Police vehicles and ambulances sped across the bridge with their sirens wailing as officers sealed off the empty square.

Some video footage showed people being evacuated from the building and others trying to hide by a wall.

The Czech government declared Saturday a national day of mourning to honour the victims.