French authorities are slowing piecing together the identities of the terrorists responsible for the Paris terror attack that claimed 129 people – with one of the gunmen believed to be Ahmed Almuhamed, who may have arrived in Europe posing as an asylum seeker.

A Syrian passport was found near the bodies of one of the militants, although its authenticity is still in question.

Serbian media have named the passport holder as Ahmed Almuhamed, 25, and say he blew himself up at the Bataclan concert hall.

A Serbian official said Almuhamed crossed into Serbia from Macedonia on October 7 as an asylum seeker.

"One of the suspected terrorists, A.A., who is of interest to the French security agencies, was registered on the Presevo border crossing on October 7 this year, where he formally sought asylum," the ministry said in a statement.

"Checks have confirmed that his details match those of the person who on October 3 was identified in Greece. There was no Interpol warrant issued against this person."

The passport found at the scene, according to Serbian media. (Blic)

Greek authorities have confirmed the Syrian passport matched one used by a refugee who arrived on the Greek island of Leros on October 3.

Security agencies had no reason to stop him because he had no criminal record.

A Greek newspaper has claimed Almuhamed was travelling with a second man, Mohammed Almuhamed, when he crossed the Serbian border.

However, CBS has quoted a senior US intelligence official as saying the Syrian passport could be a fake as it did not appear to contain the correct details.

Earlier police revealed one of the gunmen who blew himself up at the Bataclan concert hall as 29-year-old Omar Ismail Mostefai.

The Parisian had never been linked to terrorism but his father and 34-year-old brother have now been taken into custody in their hometown of Courcouronnes.

Le Monde reports Mostefaï had minor convictions on his criminal record and was the father of a young daughter born in 2010.

Police stand guard during raids in Brussels. (AAP)

Belgian police have also swooped on several properties in response to the attack. Three people have been detained in relation to a car that was found near the Bataclan concert hall where the majority of the 129 victims were killed.

The arrests were in the poor Brussels district of Molenbeek, which has been linked to several other past terror plots amid concerns Belgium has become a hotbed of European militancy.

Prime Minister Charles Michel said there had been "several" arrests and told RTBF television: "It is believed or suspected that one of these people was in Paris last night."

Belgian Justice Minister Koen Geens said separately that the arrests in Molenbeek "can be seen in connection with a grey Polo car rented in Belgium" found near the Bataclan.

"The person who rented the car was Belgian. We know this from his brother," said Geens, adding the brother had been arrested.

Parking tickets from Molenbeek were found inside the car with Belgian license plates, Belgian media said. In Paris, several witness reported that some of the attackers arrived in a vehicle with Belgian licence plates.

French police have also seized another car and have found weapons and fingerprints in the suspect vehicle.

The car, believed to have been used by the attackers who targeted a number of restaurants and bars on Friday night, was found in Montreuil, eastern Paris, according to radio station Europe 1. Several Kalashnikov assault rifles were found in the car, according to French media.

French authorities have begun the painstaking process of trying to identify the remains of the militants and are still sifting through the various crime scenes. French newspaper Le Monde reports Mostefaï was identified by his fingertip, found after he detonated a suicide vest inside the Bataclan concert hall as police closed in.

The official death toll now stands at 129, with more than 350 more injured and 99 of those in a critical condition.

The six co-ordinated attacks across Paris included:

• Two suicide bombings outside the Stade de France, where French President Francois Hollande was watching a soccer game, a friendly match between France and Germany. At least three people were killed.

• At around the same time up to four gunmen stormed the Bataclan theatre, shooting and killing at least 89 hostages who had been attending a rock concert headlined by Californian band Eagles of Death Metal.

• A man armed with an AK47 stormed popular Parisian restaurant Le Petit Cambodge, ordering diners to the ground before opening fire and killing them one by one. At least 11 people were killed.

Australian woman Emma Parkinson has been injured in the Paris attacks. (Supplied) (Supplied)

• At a nearby bar, Le Carillon, patrons were selected at random and killed, leaving bodies strewn across the street. Fourteen people were killed there, while another 12 were critically injured.

• The fifth attack happened at Cafe La Belle Equipe in central Paris, where at least 18 people were killed.

• The sixth location targeted was the busy Les Halles shopping centre.

What we know:

• Paris prosecutors say the gunmen worked in three "teams", systematically attacking their targets. Officials believe seven attackers were involved in the shooting and bombing rampage, although ISIL has suggested they had eight men involved.

• A security guard at the Stade de France has said the men had attempted to enter the arena but were turned away by security, who discovered their explosive vests when the men were frisked, the Wall Street Journal reports.

The men, who had tickets to the game, then detonated their devices outside the stadium.

• ISIL has claimed the attack in an online statement, saying the targets "were carefully chosen".

Paris attacks: A timeline of terror View Gallery

It said "eight brothers wearing explosive belts and carrying assault rifles" conducted a "blessed attack on ... Crusader France".

France is part of a US-led coalition conducting airstrikes in Iraq and Syria.

• There are reports one of the attackers was a 15-year-old boy.

• Hobart woman Emma Parkinson was among those injured, her family telling 9NEWS the 19-year-old was at the Bataclan theatre when four gunman shot and killed at least 78 people.

It is believed she is recovering in a Paris hospital, however her condition is unknown.

Foreign Minister Julie Bishop had earlier confirmed at least one Australian had been injured in the co-ordinated attacks in Paris.

"I am aware of an Australian who has been injured in the Paris attacks and we are providing consular assistance," she said in a statement.

Melbourne woman Sophie Doran, 30, was more fortunate, playing dead under a seat at the theatre while her friend nursed a bullet wound, police eventually rescuing them.

• French President Francois Hollande confirmed ISIL was behind the attacks, calling them an "act of war".

Mr Hollande said the attacks had been planned and organised from abroad, with help from people inside France, and France "will be merciless toward the barbarians of Islamic State group" and vowed to strike back.

He said the nation would observe three days of mourning and put the nation's security at its highest level.

You can watch a special edition of TODAY from 5am on Channel 9 with Karl Stefanovic in Paris.

9news.com.au will stream it LIVE.