A French police officer was shot dead and at least two others were wounded in an attack in Central Paris on Thursday night, days before the first round of the country’s presidential elections. The assailant was shot dead in the strike, for which the Islamic State group has claimed responsibility, Reuters reported.

A written note defending the extremist group was found near the attacker’s body, a judicial source told Reuters.

The attack took place in the historic boulevard of Champs-Élysées, a busy tourist area. “A little after 9 pm, a vehicle stopped alongside a parked police car. Immediately, a man got out and fired on the police vehicle, mortally wounding an officer,” Interior Ministry spokesperson Pierre-Henry Brandet said. An eyewitness to the incident said he had heard six gunshots.

Authorities have identified the shooter as a 39-year-old French national known to intelligence services for a history of violent crimes. He is believed to have been under preliminary investigation for radicalisation, but was “let go” for lack of evidence, according to The Telegraph.

According to Paris Prosecutor Francois Molins, the shooter has been identified, but investigators were trying to ascertain whether he had acted alone. The Islamic State group claimed responsibility for its shooting through its affiliated Amaq news agency. It identified the attacker as Abu Yousif al-Belgiki and said he was one of its fighters.

Earlier on Thursday, the police had issued an arrest warrant warning that a dangerous man had entered France from Belgium. But it is unclear whether this was the same suspect.

President Francois Hollande called the attack a “cowardly killing” and an act of terrorism and said the elections will be carried out with “utmost vigilance”.