The mayor of the Polish city of Gdansk has died in hospital a day after being stabbed in the heart and chest at a charity event.
He was rushed to hospital for serious abdominal injuries and underwent five hours of surgery.
A 27-year-old with a criminal record has been arrested over the attack. Police believe he used a media pass to gain entry to the stage.
Local television footage showed the suspect, who was recently released from prison, brandishing a weapon and shouting. A Gdansk city press officer Dariusz Wołodźko said the suspect came onstage shouting, and blamed the mayor and his party for his conviction and imprisonment. He reportedly said "Adamowicz is dead" and claimed he had been tortured behind bars.
On Monday, Poland's health minister confirmed Adamowicz had died from his injuries.
"We couldn't win," Lukasz Szumowski told local media.
Adamowicz was from Gdansk and had been the city's mayor for 20 years. Poland's Interior Minister, Joachim Brudzinski, described the attack in a tweet as an "act of inexplicable barbarity."
European Council President Donald Tusk had posted a message of support on Facebook, saying, "let's pray for Mayor Adamowicz. Pawel, we are with you."