Thousands of people gathered in Gdansk following the murder of Mayor Pawel Adamowicz to protest violence and hatred. Photo: Reuters / Agencja Gazeta / Dawid Zuchowicz.

A leading US Jewish advocacy organization was among the many voices on Monday mourning the death of Pawel Adamowicz, the mayor of the Polish city of Gdansk. Adamowicz was stabbed through the heart by an assassin on Sunday night as he addressed thousands of people attending a charity concert in the city.

An outspoken liberal who was frequently critical of Poland’s right-wing government on issues ranging from immigration to LBGT+ rights, Adamowicz died in hospital following over five hours of surgery.

Dr. Tomasz Stefaniak, the director of the hospital where Adamowicz was treated, said: “With the deepest regret we must confirm that unfortunately we lost the struggle for the life of the mayor of the city. We honor his memory.”

The alleged assailant, a 27-year-old man from Gdańsk with a record of violent crime, was released from prison last month, it emerged on Monday. After the stabbing, the assailant told the crowd he blamed Adamowicz’s former political party Civic Platform for his jailing in 2014 over a series of violent attacks.

Among those expressing shock at Adamowicz’s passing was the American Jewish Committee (AJC), whose office in Warsaw worked closely with the Gdansk mayor.

We are horrified to learn that Gdansk mayor Paweł Adamowicz, a longtime friend of AJC and of the Polish Jewish community, has died after being stabbed during a charity concert. May his memory be a blessing and may the killer be brought swiftly to justice. https://t.co/Y5GrOg8F6F

— American Jewish Committee (@AJCGlobal) January 14, 2019

World Jewish Congress (WJC) President Ronald Lauder said his organization was “shocked and disturbed by the horrific attack unleashed against Gdansk Mayor Pawel Adamowicz, and we extend our deepest sympathies and condolences to his family and constituents.”

“Mayor Adamowicz was a leading voice of opposition against far-right extremism, and a proponent of equal rights and security for all citizens of Poland,” Lauder continued. “He was a true friend of the Jewish community, speaking loudly and clearly against antisemitism in Poland. This was an attack not just on the mayor, but on the very value of tolerance.”

“It is our deep hope that this horrific murder will not dissuade proponents of democracy and acceptance from continuing to embrace and promote these very messages that Mayor Adamowicz carried throughout his life and career,” Lauder concluded.

Last year, Adamowicz was praised widely for his response to an antisemitic attack on a Gdansk synagogue, where an assailant threw a brick through a glass window as Yom Kippur services were coming to an end.

“Such things should not happen in the city of freedom and solidarity,” Adamowicz said at the time, in a reference to Gdansk’s status as the city where the Solidarity movement that eventually toppled communist rule in Poland first began. The following day, Adamowicz led a unity rally outside the synagogue.

Adamowicz’s death  was announced as hundreds of Gdansk’s citizens lined up outside the hospital where the mayor was treated to donate blood. On Monday evening, thousands of people marched through the center of the city to protest violence and hatred.