A gunman opened fire on French police Thursday on a renowned Paris boulevard, killing one and wounding two others before being fatally shot himself in an incident that shook France just three days before a crucial election, reports the Washington Post.

The French Interior Ministry, confirming the shooting, said two police officers were “seriously wounded” and that security forces shot and killed the attacker. The ministry said the person fired on a police car.

A spokeswoman for the Paris police, Johanna Primevert, said the gunman attacked police guarding an area near the Franklin Roosevelt metro station Thursday night at the center of the heavily traveled Champs-Élysées avenue, the Associated Press reported.

The Reuters news agency later reported one police officer died of his wounds.

There was no immediate indication of a possible motive for the attack. But French police said they have opened a terrorism investigation in the case.

Isis has now claimed responsibility for the attack, reports the Independent. Officials said the suspect had previously been flagged as an extremist. The Paris prosecutor's office said it had identified the attacker and was looking into whether he acted alone.