As early as last year Abdelhamid Abaaoud was already known to security forces after appearing, laughing, in an Islamic State video.
The fate of the suspected mastermind of the Paris attacks, Abdelhamid Abaaoud, was unknown Wednesday after a massive police raid in a suburb of the city that left at least two dead, including a female suicide bomber.
Intelligence led investigators to believe the Belgian suspect was in an apartment in Saint-Denis to the north of Paris, triggering a ferocious seven-hour shootout there with police that began before dawn.
Paris prosecutor Francois Molins said the raid had thwarted a "team of terrorists that... could have struck".
At least two people were killed -- a woman thought to have blown herself up with a suicide vest and another body that was found riddled with bullets, the prosecutor said.
Police rained more than 5,000 rounds of ammunition on the building after terrified residents living in the area near the Stade de France stadium were evacuated.
A series of explosions rang out as the police closed in on the dwelling and one suspect was seen being dragged away, his bare buttocks exposed.
Shattered BuildingAt least two bodies were found in the badly damaged building after the shootout, but their state was complicating efforts to identify them, Molins told a press conference.
The body that had sustained a number of gunshots was "not in a state that allows it to be identified", he said.
Due to the severe damage to the building, it was impossible to know how many died and who they were, the prosecutor said.
"I am not able to give you a precise number and identity of those killed. There are at least two dead and verifications will likely take longer than expected," he added.
"A new team of terrorists was neutralised and all indications are that given their arms, their organisational structure and their determination, the commando could have struck," he said.
Eight people were arrested, including two found in the rubble of the building. Salah Abdeslam, 26, suspected of taking part in the attacks in Paris with his suicide-bomber brother Brahim, was also not among those held, the prosecutor said.
Abaaoud is a 28-year-old Islamic State fighter who was previously thought to be in Syria after fleeing raids in his native Belgium earlier this year.
He is believed to have planned a number of attacks and is thought to have masterminded the gun and bomb assaults on bars and restaurants, outside the Stade de France and at the Bataclan concert hall that left 129 dead on Friday.
A key piece of the evidence in the investigation had been a mobile phone found in a bin near the Bataclan, where 89 people were killed in the worst of the bloody series of attacks.
Residents of the Paris suburb of Saint-Denis said they had been caught in a terrifying exchange of fire.
Hayat, 26, had been leaving a friend's apartment where she had spent the night when the shots erupted.
"I heard gunfire," she said. "I could have been hit by a bullet. I never thought terrorists could have hidden here."
A man arrested during the assault told AFP he had loaned his apartment to two people from Belgium.
"A friend asked me to put up two of his friends for a few days," Jawad Bendaoud said, before he was arrested.
Seven jihadists were killed or blew themselves up in Friday's attacks.
In Belgium, where some of the attackers lived, it emerged prosecutors had questioned the two Abdeslam brothers before the attacks "but they had shown no signs of being a potential threat".
Hundreds of Belgians joined a candlelight vigil in solidarity with the victims of the Paris attacks on Wednesday in Molenbeek, the troubled Brussels neighbourhood where the brothers lived.
'Don't give in to fear'The attacks in the capital were unprecedented in France, which was shaken to its core for the second time in a year after 17 people were shot dead by jihadists at Charlie Hebdo magazine and a Jewish supermarket in January.
President Francois Hollande praised security forces for their role in the "particularly perilous" operation which he said proved France was involved in a "war against terrorism".
But he urged the nation not to "give in to fear" or excessive reactions in the wake of the attacks.
"No anti-Semitic or anti-Muslim act can be tolerated," he said.
Meanwhile, the body representing Muslims in France said it would ask all 2,500 mosques in the country to condemn "all forms of violence or terrorism" at Friday prayers.
As police stepped up the hunt for the fugitives, French and Russian jets pounded IS targets in the group's Syrian stronghold of Raqa.
A monitoring group said the air strikes had killed at least 33 jihadists in the last 72 hours.
France and Russia have vowed a merciless response for the bloodshed in Paris and last month's bombing of a Russian airliner over the Egyptian Sinai peninsula which killed 229 people and was also claimed by IS.
The aircraft carrier Charles de Gaulle left France on Wednesday and is expected to reach the eastern Mediterranean by the end of the week where it will help launch intensified air strikes.
The attacks have galvanised international resolve to destroy the jihadist group and end Syria's more than four-year civil war, while potentially mending ties between Russia and France that had collapsed due to last year's Ukraine crisis.