Krakow's main market square remained sealed off on Sunday as mourners brought candles in tribute to six people killed by a gunman who authorities said was "fascinated by far-right ideologies."

The attack began shortly before 3 p.m. local time (1400 GMT) in Krakow’s historic square, a busy central spot popular with tourists. Police said a man drove into the square and began firing “at random people from his car,” in what Prime Minister Donald Tusk called an act of "terrorism."

Footage showed people fleeing in panic, with gunfire clearly audible. A passing tram was also hit, shattering windows, but no passengers were hurt.

Armed officers rushed to the scene and exchanged fire with the suspect, who was shot within three minutes of the attack beginning, which officials said prevented a further massacre. The man, 25, was arrested and remains in hospital after surgery for a gunshot wound.

Two police officers were also wounded.

Terrorism probe launched

A British national was among the dead in Poland's second city, according to police. And among the 17 wounded were nationals from Austria, Britain, Germany, Portugal and Russia, authorities told the PAP news agency.

Three more bodies were later found at the suspect's home in Ostrowiec Swietokrzyski, around 150 kilometers northeast of Krakow. Police said they were his parents and a sister.

The National Prosecutor's Office said it had launched a terrorism investigation.

"I'm absolutely devastated," said Weronika Filar, 27, a Krakow resident. "It's one of the safest places on earth... I did not expect anything like this to happen to us. Our city will never be the same."

The two police officers were wounded as they desperately chased the suspect, who was masked and dressed in military garb, including a bullet-proof vest.

The man left his car at an intersection and started shooting at the officers with a semi-automatic rifle, according to police.

One police officer was in serious but stable condition, the interior ministry said, as quoted by PAP. 

Police appealed for blood donors for the officer, named as "Jakub Kulik, who without hesitation confronted an armed attacker."

"Senior Constable Jakub Kulik and Senior Constable Artur Moranski are true heroes," Prime Minister Donald Tusk said in a post on X. "They likely saved many human lives, disregarding the risk to their own."

National mourning

On Sunday morning, the usually busy site of the attack was sealed off with red-and-white tape.

People laid candles and police checked the bags of workers at the cafes and restaurants on the square.

Most of the souvenir shops remained closed.

Black flags and Polish flags with black ribbons were seen in the city as Warsaw announced two days of national mourning for the victims from Sunday.

The traditional trumpet call from St Mary's church on the square was suspended for 12 hours to commemorate the dead, the first time this has happened since 1939, state news agency PAP reported.

In the capital, Warsaw, police said on Saturday they were strengthening security measures in busy areas popular with tourists. Barriers were installed on streets leading onto the Krakowskie Przedmiescie street in the historic heart of the capital.

The suspect was named in the media as Michal O.

The three bodies found at the gunman's home were his parents and a sister, regional police said on social media. The victims were a 53-year-old man and two women aged 52 and 21.

"Injuries were found on the bodies, which were preliminarily assessed as gunshot wounds... Seven firearms were seized from the flat," police added.

Interior Minister Marcin Kierwinski said police had also found weapons in the suspect's car.

According to investigators quoted in the Polish media, Michal O. had no previous criminal record. He was a member of a shooting club, along with his father.

Britain's Prime Minister Andy Burnham said he was "shocked and saddened by the appalling shooting."