Bells rang out and flags flew at half mast on Saturday as the Czech Republic mourned the 14 victims of the country’s worst mass shooting. The archbishop, Jan Graubner, said mass at the main St Vitus cathedral at Prague Castle and a minute of silence was observed at midday, with people stopping in streets amid heavy rain and snow, and in malls while Christmas shopping. President Petr Pavel and speakers of both houses of parliament attended the mass at the cathedral, which was packed. Similar religious services were held in other cities and towns, while many Christmas markets were closed or reduced their operations amid boosted security measures. A 24-year-old student opened fire at the faculty of arts at Charles University on Thursday, killing 13 people and then himself. Another person died in hospital later. It is one of the the worst shootings in the country in decades. The prime minister, Petr Fiala, said: “It is hard to find the words to express condemnation on the one hand and, on the other, the pain and sorrow that our entire society is feeling in these days before Christmas.” Students have lit thousands of candles at makeshift memorials at the arts faculty, and the university headquarters nearby. The school, families and friends have also started to publish the names of the victims, who include students and teachers. “This is extremely cruel news for us all,” the Institute of Musicology said on Facebook after learning its director, Lenka Hlávková, a 49-year-old mother, was among the victims. Others included the Finnish literature expert Jan Dlask and a student, Lucie Spindlerova. The gunman wounded 25 people, including three who were hit by bullets in the street as he fired from a balcony. A Dutch national and two citizens of the United Arab Emirates were among the wounded. The interior minister, Vit Rakušan, said there was no link between the shooting and “international terrorism” and that the perpetrator acted on his own. Police have since detained four people for either threatening to copy the attack or approving of it. Rakušan said police would be guarding selected sites, including schools, until 1 January at least. A police chief, Martin Vondrasek, said the gunman, previously unknown to the police, had a “huge arsenal of weapons and ammunition”. He said inspecting the crime scene was “the most shattering experience” in his 31 years of police service. Police started a search for the student when they found his murdered father earlier on Thursday. The student had told his friend he planned to kill himself in Prague. Police searched an arts faculty building where he was expected to attend a lecture, but he went instead to the faculty’s main building nearby. Police learned about the shooting at around 3pm and sent a rapid response unit to the scene. Twenty minutes later, the gunman was dead. Vondrasek said the gunman was inspired by a similar shooting in Russia, citing his social media account. After a search at the gunman’s home, police drew a link between him and the murder of a young man and his two-month-old daughter in a Prague forest on 15 December. “A ballistic analysis proved the gun used in the … forest was IDENTICAL to a gun found at the university gunman’s home,” police said on X. This week’s shooting in Prague’s Unesco-listed historic centre was the deadliest since the Czech Republic emerged as an independent state in 1993. Sympathy poured in from around the world, with Pope Francis, the US president, Joe Biden, the French president, Emmanuel Macron, Ukraine’s president, Volodymyr Zelenskiy, the UK’s King Charles and many others sending their condolences. At the makeshift memorial, a student, Antonin Volavka, lit a candle, saying: “This could have happened to anyone. Really, it could have been me.” The Czech Republic is the world’s 12th safest country, according to the 2023 Global Peace Index, and mass gun violence is rare though not unknown. In 2015, a man shot seven men and a woman dead before killing himself in a restaurant in the south-east, while in 2019 another man shot dead seven people in an eastern hospital and then himself.