GDANSK, Poland (Reuters) - Hundreds gathered at the coffin of murdered liberal mayor Pawel Adamowicz in the port city of Gdansk on Thursday as it lay in state in the museum of the Solidarity movement that helped bring down communism in Poland.

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Adamowicz’s coffin was draped in Gdansk’s scarlet coat of arms as about 2,500 people, according to police, queued after dark amid freezing wind to pay their respects. Candles placed in the shape of a giant heart stood in front of the museum.

Adamowicz, a critic of the ruling Law and Justice (PiS) party and its anti-immigrant policies, was stabbed on Sunday evening by a man who rushed the stage during a charity event. He died the following day.

Police detained at least 10 people in recent days over calls on social media to murder and acts of aggression made in the wake of Adamowicz’s death.

The incidents reflect the charged political atmosphere in a number of European countries, including Poland and Hungary, where populist leaders have fanned nationalist and anti-immigrant sentiment.

Critics have said Poland’s politicians have been cranking up hate speech and aggression in public life, and blamed the ruling PiS party for not reacting earlier.

Adamowicz was one of 11 Polish mayors who were the target of fake death certificates by a far-right group called All-Polish Youth in 2017 after they signed a declaration to welcome refugees against the government’s anti-migration policies.

The prosecutor’s office decided not to pursue the case further at the time.

Support for PiS fell to 30 percent in the wake of Adamowicz’s death, according to a poll conducted by Kantar Millward Brown for Gazeta Wyborcza daily, from 33 percent in November, while the biggest opposition grouping Koalicja Obywatelska has 25 percent.

Thousands of people gathered in vigils earlier this week in Polish cities to mourn the death of Adamowicz, who had been mayor of Gdansk for 20 years and espoused liberal causes at odds with the conservative nationalist government.

Polish authorities have arrested a 27-year-old former convict named Stefan W. in connection with the murder. His full name has so far been withheld.