(CNN) -- The mayor of the Polish city of Gdansk died on Monday, one day after he was stabbed in the heart and stomach by a man who rushed on stage during an open-air charity event, a police spokesperson confirmed to CNN.
Thousands of people witnessed Sunday's attack on Pawel Adamowicz, 53, who was rushed to hospital where he underwent a five-hour long operation before succumbing to his injuries.
Born and raised in Gdansk, Adamowicz had long been a fixture of public life in the city. He entered local politics in 1990 as a local councilor before serving as Gdansk's mayor, a position he held for more than 20 years.
The brazen attack took place during the finale of a children's hospital charity event, known as the Great Orchestra of Christmas, when Adamowicz was thanking everyone who had helped raise funds for medical equipment.
The 27-year-old suspect, who was arrested, is a Gdansk resident. He was previously convicted for bank robbery and has spent time in prison.
Asked about a motive, Gdansk city press officer Dariusz Wołodźko said the suspect came onstage shouting, and blamed the mayor and his party for his conviction and imprisonment.
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."
Photos shared on social media showed people lining up to give blood for Adamowicz on Sunday. Hundreds of people responded to Gdansk's regional center's Facebook post appealing for blood group O RhD negative, or universal donors.
"In connection with the attack on the Mayor of the City of Gdańsk and the need to make sure that blood is protected, we are asking you to give this precious medicine," the center said in the post.
Adamowicz will be remembered as a progressive voice in the country, and for his staunch support of LGBT rights, immigrants, and minority groups.
Just moments before the attack, Adamowicz shared a photo on Instagram showing a crowd of people holding white lights during the charity event. Hundreds of people have since commented with well wishes and messages of support on the post.
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