Paris attack overshadows last campaign day in France

The killing overnight of a policeman in an Islamist militant attack overshadowed the last day of France's unpredictable presidential election campaign on Friday as centrist Emmanuel Macron held onto his status as frontrunner in the polls.

An Elabe survey of voter intentions taken before the shooting on the Champs Elysees shopping street in central Paris showed Macron in front and far right leader Marine Le Pen falling further behind him.

But even leaving out the potential impact on voter sentiment of the latest deadly attack in a series that has hit France in the past two years, neither was totally assured a spot in the May 7 runoff round.

Two other candidates were snapping at their heels. The poll was conducted on Wednesday and Thursday - before the shootout in which the attacker also died and two other police officers were injured. Le Pen has made immigration and security a core part of her campaign. She wants to tighten French borders controls and build more jails, and says authorities are not doing enough to protect citizens from attacks like Thursday's. Such attacks have claimed more than 230 victims in France since January 2015. The attack that killed one officer and injured two others was quickly claimed by the Islamic State militant group.

US President Donald Trump on Friday said the deadly attack "will have a big effect" on France's upcoming presidential vote.

President Francois Hollande said he was convinced the "cowardly killing" on the Champs Elysees boulevard, in which the assailant was himself shot dead by police, was an act of terrorism. The wide avenue that leads away from the Arc de Triomphe had been crowded with Parisians and tourists enjoying a spring evening, but police quickly cleared the area, which remained empty well into the night of all but heavily armed security forces and police vehicles.

Paris Prosecutor Francois Molins said the man had been identified, but investigators were still assessing if he had accomplices. A police arrest warrant issued earlier on Thursday warned of a dangerous individual who had come into France.