French authorities have named one of the attackers as Ismail Omar Mostefai in connection with the string of terror attacks in Paris that left 129 people dead. The 29-year old suspect was a French national and among the assailants at the Bataclan concert hall.

Mostefai was identified by authorities after his finger was found at one of the attack sites. He was already known to the French police as his fingerprints matched with the authorities' record.

Mostefai's family members including his brother and father are in police custody while his home is being monitored. Mostefai is thought to be from Courcouronnes in Paris's southern suburbs.

The attacker's older brother, who is thought to have voluntarily turned himself in to the police, told the AFP before approaching investigators: "It's crazy, insane. I was in Paris myself last night, I saw what a mess it was."

Ismail's brother said that he has not been in contact with the alleged attacker for several years, who is thought to have been radicalised in 2010, but has not been involved in any terror incident since.

In the series of terror attacks, claimed by Islamic State (Isis), around 129 people have been killed and more than 350 wounded. Some of them are critically injured. Seven attackers, all of them heavily-armed, have been killed.

Meanwhile, French President Francois Hollande called the coordinated gun attack and bombings an "act of war". He said: "We will lead the fight, and we will be ruthless."

Paris chief prosecutor Francois Molins told reporters that three teams of terrorists had staged the attacks, which targeted six sites including a concert hall, a major stadium and local restaurants.

"We have to find out where they came from... and how they were financed," he said. "We can say at this stage of the investigation there were probably three co-ordinated teams of terrorists behind this barbaric act."

Despite the recent surge of terrorist violence in the French capital, Paris is likely to press ahead with holding the climate change summit by the end of November 2015. No less than 100 world leaders including US President Barack Obama will partake in the summit, which runs for more than 10 days.

"Security at UN climate conferences is always tight but understandably it will be even tighter for Paris," Nick Nutall, spokesperson for the UN climate change secretariat in Bonn, told reporters.