The dead gunman had been flagged as an extremist, according to police sources. Bystanders raise their arms as police seal off the Champs Elysees avenue in Paris, France, after the shooting of two police officers. Credit:AP Police searched a home in Seine-et-Marne presumed linked to the name on the registration of the car used in the attack, local media reported. Police were also searching a home in the town of Chelles, identified as the family home of Karim Cheurfi, a 39-year-old from Belgium with a police record. Islamic State has claimed responsibility for the shooting via its propaganda arm Amaq. It identified the attacker as one of its soldiers, naming him as Abu Yousif, a Belgian.

The attack came during a televised debate between all candidates for France's hotly-contested presidential election on Sunday. Two candidates, Francois Fillon and Marine Le Pen said they would cancel campaign events planned for Friday. Police have sealed off the Champs Elysees after a shooting. Credit:Getty In a televised statement from the presidential palace, not far from where the shooting occurred, Mr Hollande said French authorities were "convinced" that the shooting pointed to a terrorist attack. Mr Hollande, who is not running again for office, said he had convened an emergency meeting of security, defence and intelligence top officials for Friday. Police officer stand guard outside boutique shops along the Champs Elysees following the shooting. Credit:AP

"We shall be of the utmost vigilance, especially in relation to the election," he said. Gunman 'tried to run away' The counter-terrorism office has opened an investigation into the shooting. Credit:Getty Mr Brandet said the shooting occurred shortly before 9pm on Thursday (5am AEST), when a car pulled up to a police vehicle that was parked on the famous boulevard. The gunman opened fire on the police vehicle with an automatic weapon, killing an officer. Earlier reports suggested that two police officers had been shot dead, but police later said one officer had died and two others had been wounded.

A police officer stands guard after a fatal shooting. Credit:AP Mr Hollande said that a passer-by had also been wounded in the shooting, but he did not specify how badly. The gunman then "tried to leave by running away while aiming at, and trying to target, other police officers," Mr Brandet said. This photo, provided on the condition that its source not be revealed, shows Karim Cheurfi. Credit:AP "He managed to wound two others and was shot dead by the police forces," he said.

Mr Brandet said that the exact sequence of events was not clear. "It is much too early to say what the motivations were but in any case police officers were deliberately targeted this evening on the Champs-Elysees," he said. A police union Twitter account said the officers were shot while in a car stopped at a red light. Paris police spokeswoman Johanna Primevert told AP the attacker targeted police guarding the area near the Franklin Roosevelt subway station. A police source told Reuters there had been two assailants, while a witness saw one man get out of a car at the scene and begin shooting with a machine gun.

Three police sources also told Reuters it could have been an attempted armed robbery on one of the world's most expensive streets. Police urged the public to avoid the area. 'Six shots fired' One witness said he heard six shots fired, and saw the police officer hit the ground. "I came out of the Sephora shop and I was walking along the pavement where an Audi 80 was parked. A man got out and opened fire with a kalashnikov on a policeman," witness Chelloug, a kitchen assistant, told Reuters. "The policeman fell down. I heard six shots, I was afraid. I have a two-year-old girl and I thought I was going to die... He shot straight at the police officer."

The owner of a restaurant on the Champs-Elysees, who would give his name only as Denis, told France 24 television that when the shooting started, a panicked crowd of about 40 people ran into his restaurant for shelter. "Some of them were in shock, others were crying," he said. Several of the people were tourists from the US, Hong Kong and elsewhere. "They were scared," he said. "They didn't know what to do, or when it would end. They came here for holidays and didn't expect this to happen. I'm a little shocked myself and we're trying to cope with that." A Reuters reporter saw a helicopter flying low over central Paris, apparently part of a follow-up police operation.

Before the motive of the attack was known, US president Donald Trump weighed in. "It looks like another terrorist attack," he said. "What can you say? It never ends." French TV channel BFM broadcast footage of the Arc de Triomphe monument and top half of the Champs-Elysees packed with police vans, lights flashing and heavily armed police shutting the area down after what was described by one journalist as a major exchange of fire nears a Marks and Spencers store. Mr Hollande said security forces would be vigilant in the lead-up to the election, and a national tribute would be paid to the slain officer.

"We must all be aware that our security forces do work that is particularly difficult, that they are exposed, as one can see again this evening, and that they have the nation's full support," Mr Hollande said. French presidential candidate Francois Fillon called for the election to be suspended following the shooting. France has lived under a state of emergency since 2015 and has suffered a spate of Islamist militant attacks that have killed more than 230 people in the past two years. Earlier this week, two men were arrested in Marseilles. Police said they had been planning an attack ahead of the election. A machine gun, two hand guns and three kilos of TATP explosive were among the weapons found at a flat in the southern city along with jihadist propaganda materials, according to the Paris prosecutor.

NY Times, Reuters, AAP