Belgian-born Abdelhamid Abaaoud was allegedly the mastermind behind the attacks, a French official told The Guardian on Monday. Abaaoud is a 27-year-old from the Molenbeek suburb of Brussels, where other suspected militants are said to live. He allegedly wrote in Islamic State's magazine Dabiq that he had plotted attacks against the west under the nose of Belgian intelligence agencies. The Belgian news agency Belga had reported in July that Abaaoud, who is currently in Syria, had been sentenced in absentia to 20 years in prison for recruiting for ISIS after authorities failed to catch him.

Earlier on Monday, the French police intensified their hunt for the identities of the men who attacked several parts of Paris, killing 129 people on Friday. The fourth and fifth attackers were identified as Samy Amimour, a Paris resident, and Syrian passport holder Ahmad Al Mohammad. While Amimour, born in 1987, was known to the French authorities, Mohammad allegedly held a Syrian passport and came in with the refugees in Greece, The Guardian reported.

Earlier in the day, the French prime minister Manuel Valls said the police had carried out more than 150 raids across the country, including in the cities of Lyon, Toulouse, Grenoble, Jeumont and the Paris suburb of Bobigny. At least 104 people have been placed on house arrest, as raids continue in the country.

Belgian broadcasters reported that Salah Abdeslam, a 26-year-old born in Brussels, had been cornered in connection with the attacks. The French police on Sunday had released a photo of him, saying he was on the run and dangerous. He was suspected of renting the car that transported the attackers to the Bataclan concert hall, where 89 people were killed. Abdeslam is one of three brothers believed to be involved in the attacks: one was arrested in Belgium and another died in the attack, according to officials. A Flemish paper reported Abdeslam had links with Abaaoud. The other two attackers had earlier been identified as Bilal Hadfi and Omar Ismaïl Mostefai.

Seven people were detained in Belgium on Sunday in connection with the attacks, reported AFP. A Belgian official said two of the seven men who were wearing suicide vests were French nationals living in Brussels, along with another man who was arrested. Officials said that three teams of attackers were involved and seven suicide bombers blew themselves up: three near the national stadium, three at the Bataclan concert hall and one nearby to it.