U.S. President Donald Trump on Thursday evening commented on the shooting in Paris, saying it looked like the latest in a string of terror attacks that has hit France.

“Our condolences from our country to the people of France,” Trump said at a joint press conference with Italian Prime Minister Paolo Gentiloni.

“Again, it is happening again seems. I just saw it as I was walking in, so that's a terrible thing. It is a very, very terrible thing that's going on in the world today but it looks like another terrorist attack. What can you say? It just never ends. We have to be strong and we have to be vigilant and I have been saying it for a long time,” he added.

A police officer was killed in the shooting on the Champs-Elysees.

One man who opened fire on the police was shot and killed by officers on the scene, Reuters reported.

Police said multiple shooters were involved in the attack, adding that the incident appeared to be an act of terrorism.

The shooting comes just three days before the first round of voting in the French presidential election. National Front chairwoman Marine Le Pen, a staunch nationalist and opponent of large-scale Muslim immigration to France, is widely expected to win one fifth to one quarter of the initial vote and advance to the runoff election in May.

France has been rocked by a wave of deadly jihadist attacks which began on January 2015 and have killed more than 230 people. The country remains on high alert.

Just this week, French security services arrested two men accused of plotting an attack.

Last month, French authorities arrested four members of a family as part of a preliminary investigation in connection with a plot to carry out an attack

Prior to that, French police arrested three men suspected of planning a terror attack in raids in the Paris area, Marseille and the central city of Clermont-Ferrand.