US President Donald Trump on Friday said a deadly attack in Paris claimed by the Islamic State group “will have a big effect” on France’s upcoming presidential vote.

“Another terrorist attack in Paris. The people of France will not take much more of this. Will have a big effect on presidential election!”

Trump tweeted hours after a gunman shot dead a policeman and wounded two others on the world-famous Champs-Elysees boulevard.

The attack, claimed by the Islamic State, rocked France’s presidential race Friday with just days to go before one of the closest elections in recent memory.

Meanwhile, French Prime Minister Bernard Cazeneuve on Friday accused far-right presidential candidate Marine Le Pen of seeking to use the attack for political gain.

Cazeneuve, a Socialist, said Le Pen’s National Front (FN) “after each attack, seeks to exploit it and use it for purely political means.”

French Prime Minister Bernard Cazeneuve speaks next to Interior Minister Matthias Fekl (L) and Justice Minister Jean-Jacques Urvoas after a meeting of the Defense Council on April 21, 2017 at the Elysee Palace in Paris, after a gunman opened fire on police on the Champs Elysees. (THOMAS SAMSON / AFP)

French Prime Minister Bernard Cazeneuve speaks next to Interior Minister Matthias Fekl (L) and Justice Minister Jean-Jacques Urvoas after a meeting of the Defense Council on April 21, 2017 at the Elysee Palace in Paris, after a gunman opened fire on police on the Champs-Elysees. (Thomas Samson/AFP)

Bloodshed had long been feared ahead of Sunday’s first round of voting after a string of jihadist atrocities since 2015, and shooting on the world-renowned boulevard forced security to the top of the agenda in the campaign.

Three of the four frontrunners called off campaign events planned for Friday in the wake of the attack.

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, which have killed over 230 people.

The swift claim by IS indicated the group may have been trying to capitalize on the widespread attention from a high-profile attack at a time when Islamic extremism and security are at the center of France’s presidential campaign.

French presidential election candidate for the right-wing Les Republicains (LR) party, Francois Fillon delivers a statement to the press at his campaign headquarters in Paris on April 21, 2017. (Patrick KOVARIK / AFP)

French presidential election candidate for the right-wing Les Republicains (LR) party, Francois Fillon delivers a statement to the press at his campaign headquarters in Paris on April 21, 2017. (Patrick Kovarki/AFP)

Meanwhile French conservative candidate Francois Fillon has pledged to keep the country under a state of emergency following the Paris attack.

In a statement at his campaign headquarters, Fillon said “the fight for the French people’s freedom and security will be mine. This must be the priority” of the next president.

Fillon promised to boost police and military forces.

He also said that, if elected, he would launch a “diplomatic initiative” aiming to create an international collaboration against Islamic extremists that would include all major actors, including the United States, the European Union, Russia, Iran, Turkey and the Gulf countries.

Fillon hopes his experience as prime minister from 2007 to 2012 and hardline views on security issues will give his campaign a boost, just two days before the first round of the vote.

The two top contenders Sunday will advance to the runoff on May 7.