Paris attacks: Manhunt underway as authorities identify three brothers

The report has quoted authorities a saying that public help has been sought in finding one of them.

The French authorities said they were seeking Salah Abdeslam, 26, and described him as dangerous.

Belgian officials said that one of his brothers had died in the three-hour massacre, which left at least 129 people dead. Another brother is in detention in Belgium.

Officials had initially described eight attackers, but on Saturday night said that only seven attackers had died - six by blowing themselves up and one in a shootout with police.

One attacker reportedly posed as a Syrian migrant.  The Serbian newspaper Blic published a photograph of a passport page that identified its holder as Ahmad al-Mohammad, 25, a native of Idlib, Syria. He passed through the Greek island of Leros on Oct. 3 and the Serbian border town of Presevo on October 7, officials in those countries said. It was not clear whether the passport was authentic.

At least three other attackers were French citizens. Of them two had been living in the Brussels area, including one in Molenbeek, according to the Belgian authorities. The third was Ismael Omar Mostefai, 29, a native of Courcouronnes, France, who had been living in Chartres, 60 miles southwest of Paris, and who, along with two other gunmen, killed 89 people at the Bataclan concert hall.

Mostefai was the middle of five children born to an Algerian father and a Portuguese mother, and he once worked at a bakery, according to a former neighbor at the housing development just outside Chartres where the family used to live.

As the authorities continued to examine Mostefai's motivations and background, other clues emerged from official accounts in France and Belgium.

Mostefai was identified in a Facebook post by the mayor of Chartres, Jean-Pierre Gorges. He was one of three hostage-takers at the Bataclan, and who was identified based on a print from his severed finger.

Mostefai was born in the town of Courcouronnes and grew up around Chartres, where he lived until 2012. According to the Paris prosecutor, Francois Molins, he was arrested in connection with a series of low-level crimes from 2004 to 2010 and had been under surveillance since 2010, having been flagged in a French security services database as someone who had fallen under the influence of extremist Islamist beliefs.

Six of his relatives have been detained for questioning; on Sunday, other relatives told French television that he had been estranged from them after a falling-out.