Polish media have reported that Pawel Adamowicz, Mayor of the Polish town Gdansk, was stabbed in the heart at a charity event.

The 53-year-old was resuscitated by paramedics at the scene of the incident on Sunday evening but was pronounced dead later in hospital. “Despite all our efforts, we failed to save him,” director of Gdansk University hospital, Dr Tomasz Stefaniaktold said.

Video footage of the attack then surfaced online, showing a 27-year-old man bursting onto the podium to attack Mr Adamowicz, stabbing him before grabbing the microphone to declare he had been wrongly jailed and tortured by the previous centrist government of the Civic Platform. “That’s why Adamowicz dies,” the attacker proclaimed.

The man was quickly arrested by police.

Vigils are now being held across Poland to mourn Pawel Adamowicz, who had been mayor of Gdansk for 20 years.

The city flag in Gdansk was lowered to half-mast and officials have announced that Adamowicz’s funeral will see the country enter a national day of mourning.

Adamowicz was known for his liberal political views and opposing the ruling right-wing party on issues such as LGBT+ rights in Poland.

European Council President Donald Tusk, also a Gdansk native, expressed his sadness on Twitter, writing, “Paweł Adamowicz, Mayor of Gdańsk, a man of Solidarity and freedom, a European, my good friend, has been murdered. May he rest in peace.”

Paweł Adamowicz, Mayor of Gdańsk, a man of Solidarity and freedom, a European, my good friend, has been murdered. May he rest in peace.

— Charles Michel (@eucopresident) January 14, 2019

He also flew into his hometown to mourn the late politician, addressing Mr Adamowicz: “You were always there whenever there was the need to be good and courageous and to take a stand against evil.”

Thousands also attended a gathering in Warsaw where they were addressed by that city’s mayor Rafal Trzaskowski, who spoke under a banner that read, “Stop the hate.”

The European Parliament also held a minute of silence.

Gdansk resident Agnieszka Naruszewicz described Adamowicz as “kind, friendly, smiling” and said that he will be dearly missed.

“The spiral of violence has gone too far in Poland,” she added.

Adamowicz marched along the LGBT+ community at last year’s Gdansk Pride Parade and said that he dreamed of a day when “equality and fraternity can become a part of Poles’ daily lives.”