A home in the suburbs of Paris has been searched by authorities after a gunman opened fire on police on the Champs-Elysees boulevard, killing one officer and wounding three people before being shot dead.
The attacker emerged from a car and used an automatic weapon to shoot at officers outside a Marks & Spencer store at the centre of the Champs-Elysees, anti-terrorism prosecutor Francois Molins said.
The gunman was shot dead by other officers, and a woman tourist was also wounded in the incident on Thursday night.
A terror investigation has been launched and authorities searched a home early on Friday in an eastern suburb of Paris believed to be linked to the shooting. A pump-action shotgun and knives were found in the gunman’s car.
A police document obtained by The Associated Press identifies the address searched in the town of Chelles as the family home of 39-year-old Karim Cheurfi, who has a criminal record.
Police have detained three of his family members for questioning, as investigators seek to determine whether he was acting alone and where he got his weapons.
The so-called Islamic State claimed responsibility just a few hours after the attack.
The extremist group gave a pseudonym for the gunman, Abu Yusuf al-Beljiki, indicating he was Belgian or had lived in Belgium, although Belgian authorities said they had no information about the suspect.
Two French officials said the gunman had been detained towards the end of February after speaking threateningly about the police, but he was then released due to a lack of evidence.
He was also convicted in 2003 of attempted murder in the shooting of two police officers.
The first round of the presidential election is to take place on Sunday and candidates have since cancelled or rescheduled their final campaign events ahead of it.
Conservative contender Francois Fillon, who has campaigned against “Islamic totalitarianism”, said he was cancelling his planned campaign stops on Friday.
Far-right candidate Marine Le Pen, who campaigns against immigration and Islamic fundamentalism, cancelled a minor campaign stop, but scheduled another.
Centrist candidate Emmanuel Macron offered his thoughts to the family of the dead officer and Socialist Benoit Hamon tweeted his “full support” to police against terrorism.
A French television station hosting an event with the 11 candidates running for president briefly interrupted its broadcast to report the shootings.
French president Francois Hollande said he was convinced the circumstances of the attack pointed to a terrorist act.
A Downing Street spokesman said: “The UK strongly condemns the appalling terrorist attack in Paris.
“The Prime Minister has tonight passed on her condolences to President Hollande.”
US president Donald Trump said the shooting “looks like another terrorist attack” and sent condolences to France.
US vice president Mike Pence said the shooting was the “latest reminder that terrorism can strike anywhere, any time” and his country “will not relent in our effort to end terrorism”.
Australian prime minister Malcolm Turnbull offered his condolences to the killed policeman and urged Australians in Europe to be on their guard.