WARSAW, Poland (AP) – The popular Liberal mayor of the Polish port city of Gdansk died on Monday after being stabbed at a charity event by a former detainee who stormed on the scene and said that it was a revenge against the country's main opposition. Party.

Pawel Adamowicz, 53, has died of heart and abdominal injuries despite efforts to save him, involving a five-hour operation and blood transfusions, said Health Minister Lukasz Szumowski .

"The fight for his life has been lost," said Szumowski.

The assassination of Adamowicz, a mayor of six warrants who often interfered freely with the citizens of his city, shocked Poland.

Even before his death was announced, marches against violence were planned for the evening in Poland. In Gdansk, the city's flag was lowered by half and Masses were planned, including one in Warsaw, to which Prime Minister Mateusz Morawiecki was planning to attend.

The ruling party, Law and Justice, has faced accusations that an atmosphere of hatred against Adamowicz and other liberal political opponents contributed to the attack.

Government officials reacted against this accusation, strongly denouncing the attack and pointing out that the perpetrator of the violence, aged 27, had a history of robbery in a bank and mental illness.

The former convict rushed to the scene with a knife Sunday and stabbed Adamowicz. He then grabbed a microphone and said that it was a revenge against the opposition party Civic Platform, which Adamowicz belonged to for many years.

Identifying him as being Stefan, he said he was wrongfully imprisoned under a government led by the Civic Platform.

"I was imprisoned but innocent," he told thousands of people. "Civic platform m & # 39; tortured. That's why Adamowicz just died. "

Donald Tusk, founder of Civic Platform, Prime Minister during the incarceration of the assailant and currently President of the European Council, was traveling to Gdansk, his hometown, to introduce himself, said an assistant.

"Pawel Adamowicz, mayor of Gdansk, a man of solidarity and freedom, European, my good friend, was murdered. May he rest in peace, "tweeted Tusk.

Deputy Attorney General Krzysztof Sierak said that questions had been asked about the mental state of the attacker, who had used a 14.5 cm (5.5 inch) knife on Adamowicz and that two psychiatrists l & # 39; would consider. He had served five and a half years in prison and had been released by the end of last year. On Monday, he was charged with murder.

Adamowicz, mayor of the city for more than 20 years, grabbed his belly and collapsed in front of the public during the "Lights to Heaven" fundraiser organized by the Grand Orchestra of Christmas charity . Earlier in the day, he went to the streets of his city to collect money with volunteers across the country. He had talked about tolerance and love just before being stabbed.

Jerzy Owsiak, the head of this charity, announced Monday that he was resigning his post but that he would continue to work with the organization, which raises funds to equip children in hospitals to short of money.

Owsiak said that he had himself been the target of threats and hate messages, including from lawmakers on the right, but that he was not receiving any help from the police.

He said at a press conference that recently, the level of public criticism concerned "Nazism, fascist language and threats".

The attack caused a wave of grief. Many gave blood in Gdansk on Monday. Some said that they had free time to help save Adamowicz.

The leader of the ruling party, Jaroslaw Kaczynski, the most powerful politician in the country, expressed his "great pain" and his solidarity with the Adamowicz family.

Critics of the government, however, believed that the animosity expressed against Adamowicz by officials of the Kaczynski party, sometimes broadcast on national television, as well as extremists from other groups, played a role.

Adamowicz was part of the democratic opposition formed in Gdansk under the leadership of Lech Walesa in the 1980s. After leaving Civic Platform, he was re-elected for a sixth term as an independent candidate in the fall.

As mayor, he was a progressive voice, supporting sexuality education in schools, LGBT rights and tolerance of minorities. He showed solidarity with the Jewish community when the Gdansk synagogue had windows broken last year, strongly denouncing vandalism.

Adamowicz also pleaded for the medical treatment of the wounded Syrian children in Gdansk, a plan blocked by the Law and Justice government. After taking a stand, a far – right group, Polish Youth, published what they called a "political death notice" from Adamowicz.

The last politically motivated attack in Poland took place in 2010 in Lodz, when a man shouted that he wanted to kill Party leader Law and Justice, Jaroslaw Kaczynski, killed a party lawmaker assistant in the European Parliament.

Kaczynski, then leader of the opposition, blamed the attack on a "climate of hate" as part of the Civic Platform.

Adamowicz is survived by his wife and two daughters. Funeral arrangements have not yet been announced, although the president has said that the day of the funeral would be a day of national mourning.