A gunman believed to have been inspired by far-right ideology has killed six people and injured more than a dozen in an attack in the busy centre of Poland's second largest city.

Police said the attacker drove onto Main Market Square in Krakow on Saturday and began randomly firing at people.

The attacker, who was equipped with military-style weapons and attire, was shot and subdued by police, one of whom was critically injured in the process.

The 25-year-old Polish man - described by one minister as "ultra-nationalist" - survived and is in custody.

Poland's Prime Minister Donald Tusk said three bodies were later found at the suspect's home.

He said: "Until now in Poland we haven't had such drastic cases of terrorism...…