Police said the attacker drove on to Main Market Square in Krakow, a popular tourist attraction, on Saturday afternoon and fired randomly at people.
Four women and two men were killed. Three were Polish, one was British and two have not been identified.
Among the 16 injured are five foreign nationals from Austria, Germany, Portugal, Russia and Britain, BBC reported.
Another three bodies were found when counter-terrorism police searched the suspect’s home around 125 miles (200km) away, Polish Prime Minister Donald Tusk said.
A massive armed police presence was deployed across Krakow on Saturday evening, as security measures were ramped up in the capital Warsaw and elsewhere.
