A 24-year-old Czech student has shot dead his father then killed 14 people and wounded 25 others at his Prague university before possibly killing himself, marking the country’s worst-ever mass shooting.

The government declared a day of mourning across the central European country for December 23 to remember the victims, decided at a special cabinet meeting with Prime Minister Petr Fiala and President Petr Pavel.

“I would express my great sadness along with helpless anger at the unnecessary loss of so many young lives,” Pavel said.

“I would like to express my sincere condolences to all relatives of the victims, to all who were at this tragic incident, the most tragic in the history of the Czech Republic.”

Police – who discovered a large arsenal of weapons at the downtown Prague Charles University building where the shooting took place on Thursday afternoon – were tipped off earlier in the day the suspect was likely heading to Prague from his town in the Kladno region outside the capital with intentions of taking his own life.

Shortly after that, the shooter’s father was found dead.

Police evacuated an arts faculty building where the shooter was due to attend a lecture, but then were called to the faculty’s larger main building, arriving within minutes after reports of the shooting, Police President Martin Vondrasek said.

Police had “unconfirmed information from an account on a social network that he was supposedly inspired by one terrorist attack in Russia in the autumn of this year”, Vondrasek told reporters, adding the shooter was a legal holder of several firearms.

“It was a premediated, horrific act that started in the Kladno region and unfortunately ended here.”

The gunman is also suspected in the killings of another man and his two-month-old daughter who were found last week shot dead in woods in a village outside Prague, Vondrasek said.

The gunman’s death was likely a suicide but authorities are also investigating whether he may have been killed by police who returned fire, he said.

Police said he was a high-achieving student with no prior criminal record and he acted alone.

Police asked not to reveal the man’s identity but his name reported by some Czech media matched a police search report.

Interior Minister Vit Rakusan said the shooting had no connection to international terrorism.

Authorities sealed off the square and area adjacent to the faculty building, in a busy historical district across the river from Prague Castle on a popular street leading to Old Town Square.

Media images showed students fleeing the building with their hands in the air, and others perched on a ledge near the roof trying to hide from the attacker while students barricaded classrooms with desks and chairs.

“We always thought that this was a thing that did not concern us. Now it turns out that, unfortunately, our world is also changing and the problem of the individual shooter is emerging here as well,” Prague mayor Bohuslav Svoboda told Czech Television.

The White House condemned the shooting and said the United States was ready to offer assistance. 

Leaders across Europe including France’s Emmanuel Macron offered their support.

Witness Ivo Havranek, 43, told Reuters via Zoom that he initially thought the “couple of bangs” he heard might have come from loud tourists or a nearby movie set.

“Then suddenly there were students and teachers running out of the building. I went through the crowd not realising what is actually going on. I wasn’t ready to admit that something like that could happen in Prague,” he said. Only once he saw police officers with automatic rifles, he knew it was serious, he said.

“They shouted at me to run away.”

People lit candles outside the historic headquarters of Charles University, central Europe’s oldest set up in 1348.

Gun crime is relatively rare in the Czech Republic. In December 2019, a 42-year-old gunman killed six people at a hospital waiting room in the eastern Czech city of Ostrava before fleeing and fatally shooting himself, police said.

In 2015, a man fatally shot eight people and then killed himself at a restaurant in Uhersky Brod.