PARIS — France identified a 27-year-old Belgian who once boasted about killing “infidels” and fought for the Islamic State group in Syria as the mastermind of the Paris attacks, and President Francois Hollande vowed Monday to forge a united coalition capable of defeating the jihadists at home and abroad. Addressing lawmakers after France observed a minute of silence honoring the 129 people killed and 350 wounded, Hollande said the victims came from at least 19 nations, and the international community, led by the United States and Russia, must overcome its deep-seated divisions over Syria to destroy the Islamic State on its home turf. French and other Western intelligence agencies face an urgent challenge to track down the surviving members of the three Islamic State units who inflicted the unprecedented bloodshed in France and, perhaps more important, to target their distant commanders in Islamic State-controlled parts of Syria. A French security official said antiterror intelligence officials had identified Abdelhamid Abaaoud, a Belgian of Moroccan descent, as chief architect of the attacks on a rock concert, a soccer game and popular nightspots in one of Paris’ trendiest districts. The official cited chatter from Islamic State figures that Abaaoud had recommended a concert as an ideal target for inflicting maximum casualties, as well as electronic communications between Abaaoud and one of the Paris attackers who blew himself up. French Interior Minister Bernard Cazeneuve said police seized a Kalashnikov assault rifle, three automatic pistols and a bulletproof vest from a suspected arms dealer with jihadist sympathies, and a rocket launcher and other military-grade gear from his parents’ home. Seven attackers died — six after detonating suicide belts and a seventh from police gunfire — but Iraqi intelligence officials told the Associated Press that their sources indicated 19 participated in the attack and five others provided hands-on logistical support. On Monday, Belgian police in balaclavas, gas masks and body armor raided Abdeslam’s suspected hideout in the Molenbeek district of Brussels but came out empty-handed. Determined to root out jihadists within French communities, Hollande said he would present a bill Wednesday seeking to extend a state of emergency — granting the police and military greater powers of search and arrest, and local governments the right to ban demonstrations and impose curfews — for another three months. In hopes of killing Islamic State organizers and trainees, France overnight launched its heaviest air strikes yet on the city of Raqqa, the group’s de facto capital in Syria.