The Paris prosecutor, François Molins, said the attackers were all armed with assault rifles and suicide vests. Their assault began at 9:20 p.m. Friday, when one terrorist detonated a suicide bomb outside the gates of the soccer stadium on the northern outskirts of Paris. It ended at 12:20 a.m. Saturday when the authorities stormed a concert hall, the Bataclan. One attacker there was killed; two others detonated suicide vests. Inside the hall, 89 people, who had been listening to a rock band, had been shot to death.

The man with the Syrian passport — which Greek officials said had been registered at the Aegean island of Leros on Oct. 3 — was 25, and died at the stadium. Another assailant, who died at the concert hall, was 29 and a native of Courcouronnes, about 20 miles south of Paris. He had a criminal record and was known to be involved in extremist Islamic ideology, Mr. Molins said. Officials later identified him as Ismaël Omar Mostefaï and said they had detained several of his relatives for questioning.

The hunt for possible accomplices of the terrorists gained steam on Saturday. Officials in Belgium announced three arrests, one of them linked to a rental car found in Paris. In Germany, the police were exploring whether a man they arrested last week with weapons in his car and his GPS navigator set for Paris was linked to the attacks. But it remained unclear how a plot of such sophistication and lethality could have escaped the notice of intelligence agencies, both in France and abroad.