The Islamic State claimed responsibility after one police officer was killed in a rare exchange of gunfire on the famed Champs-Elysees in central Paris just days before a critical presidential election.

Two other officers were seriously wounded in the attack in the popular tourist area in central Paris. The gunman was killed by police.

The Islamic State identified the attacker as Abu Yusuf al-Beljiki through its Amaq news agency, according to SITE Intel Group, a U.S.-based organization that monitors terrorists' activity online.

French President Francois Hollande said he is convinced the circumstances of the Paris shooting points to terrorist act, the Associated Press reported.

Paris police spokeswoman Johanna Primevert told AP the gunman deliberately targeted police on guard near the Franklin Roosevelt subway station. She said he appeared to act alone.

Interior Ministry spokesman Pierre-Henry Brandet told BFM television that a man stepped from a car and opened fire on a police vehicle. A witness told Reuters that the attacker opened fire with a machine gun.

Security has been high in France leading up to the first round of hotly contested presidential elections Sunday. A French station hosting a televised event with the 11 candidates briefly interrupted its broadcast to report the shootings, AP reported.

As police blocked off key roadways in the heart of the French capital and told people to avoid the area, the broad avenues leading to the Arc de Triomphe were awash in police vehicles decked with whirling blue lights.

French prosecutors opened a terrorism investigation into the attack. Two police officers told AP the attacker had been flagged as an extremist, but offered no further details. The officers spoke to AP on the condition of anonymity to share information about the ongoing investigation.

In Washington, President Trump said the shooting in Paris “looks like another terrorist attack."

"It just never ends, We have to to be strong and we have to be vigilant, and I've been saying it for a long time," he added.

France has lived under a state of emergency declared following a terrorist attack in November 2015 that left 130 dead.