The gunman who shot dead a policeman in Paris on Thursday has been identified from papers left in his car, but French officials are yet to release his name.
Local media say the 39-year-old lived in the city's suburbs, and had been seen as a potential Islamist radical.
French police are also hunting for a man who has been identified by Belgian security services, an interior ministry spokesman says.
The gunman was killed by security forces on the Champs-Elysees.
He had also wounded two police officers.
President François Hollande is to chair a security cabinet meeting, as France readies for Sunday's presidential poll.
Mr Hollande said he was convinced the attack was "terrorist-related", adding that the security forces had the full support of the nation and a national tribute would be paid to the fallen policeman.
So-called Islamic State (IS) said one of its "fighters" had carried out the attack.
A car pulled up alongside a police bus just before 21:00 (19:00 GMT) and a man got out, opening fire on the bus with an automatic weapon, Interior Ministry spokesman Pierre-Henry Brandet said.
After killing an officer, the man attempted to run away while shooting at other officers, two of whom he injured, the spokesman added.
He was then shot dead by security forces.
Terrified eyewitness later recounted scenes of panic as they ran for cover after hearing gunfire.
The whole of the Champs-Elysees was evacuated.
Because of its worldwide renown and its large number of visitors, the avenue has long been seen as a potential target, the BBC's Hugh Schofield in Paris reports.
Overnight, a property in the eastern Parisian suburb of Chelles was searched by investigators, who want to know who else - if anyone - may have known about the gunman's plans.(Source: BBC)