Polish officials say the 24-year-old suspect held far-right and ultra-nationalist views. Police later found his parents and sister dead at the family home.
A British national was among six people killed when a gunman opened fire in the main market square of Kraków, Poland, on Saturday afternoon. Prosecutors have opened a terrorism investigation.
At least 15 people were wounded, including nationals of Britain, Austria, Germany, Portugal and Russia. Two police officers were also injured, one of them seriously.
Poland has begun two days of national mourning.
The suspect, a Polish national named in local media as Michał O, drove at speed into the square in the heart of the old town at about 3pm, police said.
Wearing military-style fatigues and a bulletproof vest, he began shooting at random during what a Kraków police spokesperson, Katarzyna Cisło, described as a “wild ride” around the square.
He was wounded in an exchange of fire with police, arrested and taken to hospital, where he underwent surgery. He remains under heavy police guard and was reported to be in a critical condition.
Four women and two men were killed. Besides the British victim, three were Polish women and two have not yet been identified. Media reports said the suspect had a valid gun licence and no previous criminal record.
Police later found the bodies of the suspect’s father, 53, mother, 52, and sister, 21, at the family home in Ostrowiec Świętokrzyski, about 150km (90 miles) north-east of Kraków. They had probably died of gunshot wounds.
Daniel Prokopowicz, a spokesperson for the National Prosecutor’s Office, said it was “highly likely” that the killings in both places were carried out by the same person, but that investigations were continuing.
The office said it was investigating “the killing of six people … using a firearm, and the attempted murder of many others, including police officers, this act constituting a terrorist offence”.
Interior minister Marcin Kierwiński said the suspect was fascinated with far-right ideologies and held “very radical” and “ultra-nationalistic” views.
Defence minister Władysław Kosiniak-Kamysz called the shooting an “act of terror” against the people of Kraków, Poland’s second-largest city.
Kraków’s main square, which most of the city’s 15 million annual visitors pass through, remained partially closed on Sunday. Mourners left candles near the scene. Flags across Poland flew at half mast, as did EU flags outside the European Commission in Brussels.
The traditional hourly trumpet call from St Mary’s Basilica on the square was suspended for 12 hours, the first time that has happened since 1939, according to the Polish Press Agency. Police in Warsaw said security had been stepped up in the capital.
Rzeczpospolita, a leading Polish newspaper, said in an editorial that the attack marked a “brutal end to an era in which Poland was considered an island of safety”.
Prime Minister Andy Burnham said: “I’m shocked and saddened by the appalling shooting in Kraków today. My thoughts are with the families of those who have lost their lives, everyone injured and all those affected by this senseless violence.”
Ukrainian president Volodymyr Zelensky called it a shocking crime and said Ukraine stood in solidarity with its neighbour. French president Emmanuel Macron spoke of “shock and disbelief”, and German chancellor Friedrich Merz said Germany stood with Poland “as a friend and partner in these difficult times”.
Italy’s prime minister, Giorgia Meloni, condemned a “vile and unacceptable act of violence”.
British travellers can check the latest Foreign Office travel advice for Poland.
The shooting has shocked a country long considered safer than many of its western European neighbours. In October, a series of school stabbings left one woman dead; officials linked them to extremist content online.
It also comes at a tense time in Polish politics. The country is gripped by a crisis over the make-up of its Constitutional Tribunal, which has pitted Prime Minister Donald Tusk’s government against President Karol Nawrocki.
Late last month, Nawrocki tried to enter the tribunal’s building as police surrounded it. The opposition has accused the government of attempting a coup, while the government says it is restoring the rule of law after years of political interference in the courts. Tusk has since sought a one-to-one meeting with the president to ease tensions.
Officials have attributed the attack to the suspect’s far-right and ultra-nationalist views.