A major blood collection is underway in Poland in an effort to help save the life of Paweł Adamowicz, the mayor of northern city Gdansk, who was stabbed on stage in front of thousands of people during a charity concert in an apparent assassination attempt.

Mr Adamowicz underwent a five-hour operation after suffering stab wounds to his heart and abdomen, and is said to be in a critical condition.

The mayor, who has served since 1998, grabbed his stomach and collapsed in front of the audience at the 27th annual fundraiser organised by the Great Orchestra of Christmas Charity.

He was resuscitated at the scene and then transported to the Medical University of Gdansk.

One of the surgeons, Dr Tomasz Stefaniak, sparked applause early on Monday morning when he told reporters “the patient is alive”.

But he said Mr Adamowicz was in “very, very serious condition” after he suffered a “serious wound to the heart, a wound to the diaphragm and to the internal organs.”

He said the coming hours would be decisive and asked for thoughts and prayers for the mayor who was part of the democratic opposition formed in Gdansk under the leadership of Lech Walesa in the 1980s.

Television footage of the incident showed the mayor speaking to the crowd while holding a sparkler, before his attacker moved towards him.

After carrying out the attack, the man shouted from the stage that he had been wrongly imprisoned under a previous national government led by Civic Platform, a party to which the mayor formerly belonged.

He said his name was Stefan and told the crowd: “I was jailed but innocent. Civic Platform tortured me. That's why Adamowicz just died.”

Police said the suspect was a 27-year-old who was recently released from prison where he had served a term for bank robberies.

Police spokesman Mariusz Ciarka said the attacker appeared to have mental health problems and gained access to the area with a media badge. It was unclear how he acquired the credential.

He was arrested and is under investigation.

Mr Adamowicz has been a progressive voice in Polish politics, supporting LGBT+ rights and tolerance for minorities. He marched in last year's gay pride parade, a rare action for a mayor in Poland.

He also made efforts to support the Jewish community when the city's synagogue had its windows broken last year, strongly denouncing the vandalism.

A man is held on the ground by security staff after the attack on the mayor of Gdansk during a charity event (AFP/Getty Images)

The fundraising event in Gdansk, known as the Grand Finale, was organised by the Great Orchestra of Christmas Charity to collect money for Poland’s cash-strapped hospitals.

It is believed the stabbing took place as crowds gathered in the city for the traditional “Lights to the Sky” fireworks display.

War games in Poland Show all 25 1 /25 War games in Poland War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Photos Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato War games in Poland Nato

Gdansk Archbishop Leszek Slawoj Glodz, who was at the hospital during the operation on Mr Adamowicz, said he was praying for a “miracle”.

Support free-thinking journalism and attend Independent events