President Donald Trump says a shooting in Paris today 'looks like another terrorist attack.'

The U.S. president addressed the assault on two police officers at a news conference Thursday afternoon.

'It just never ends,' he said of the terror threat from the White House's East Room.

French police say the incident involving at least two gunman was probably a 'terrorist act.'

President Donald Trump says a shooting in Paris today 'looks like another terrorist attack.'

White House press secretary Sean Spicer said just before the news conference began that Trump had been briefed on the shooting that happened while he was meeting with the Italian prime minister.

'Condolences from our country to the people for France again. It's happening it seems,' Trump said from the podium. 'I just saw it as I was walking in, so it's a terrible thing and it's a very, very terrible thing that's going on in the world today.'

Trump did not comment on the assault at the top of his remarks but said after he was asked for a reaction, 'It looks like another terrorist attack, and what can you say? It just never ends.

'We have to be strong, and we have to be vigilant, and I've been saying it for a long time,' Trump told Fox News' John Roberts.

France is in the process of holding a national election. The first round of voting begins on April 23.

A gunman wielding an AK-47 killed one police officer and wounded another today on the Champs-Elysees. The assailant was killed in the showdown with police, Paris police have said. Another suspect is believed to have been involved, as well.

Police just two days ago arrested two men in southern Marseille with weapons and explosives who were suspected of preparing an attack to disrupt the first-round of the presidential election on Sunday.

France is in a state of emergency and at its highest possible level of alert since a string of terror attacks that began in 2015 and have killed over 230 people.

Thousands of troops and armed police have been deployed to guard tourist hotspots such as the Champs Elysees or other potential targets like government buildings and religious sites.

Police closed off the popular avenue (pictured) after a policeman was killed during a shooting incident in the French capital

A French police officer was tonight shot dead on the Champs Elysees in Paris (pictured) - just as presidential candidates took part in a TV debate nearby

Up until now, polls showed voters more concerned about unemployment and their spending power than terrorism or security, though analysts warned this would change in the event of further bloodshed.

For weeks, centrist Emanuel Macron and National Front (FN) leader Marine Le Pen have been out in front.

Scandal-plagued conservative Francois Fillon and far-left firebrand Jean-Luc Melenchon have closed the gap substantially in the last two weeks.

Opinion polls now show there is a chance that any of the four leading candidates could reach the second-round run-off on May 7 if none of them reach a majority in this weekend's election.