Paris: The fate of the alleged ringleader of the Paris terror attacks remained unclear 24 hours after a pitched battle erupted at a terror cell safe-house in the city's north.

Despite reports that Islamic State operative Abdelhamid Abaaoud, 27, had been in the apartment and was killed in the Wednesday morning shootout with police, there was no official confirmation overnight.

The raid, which saw 110 police from elite anti-terror units fire 5000 rounds, left at least two people dead, one identified as a female suicide bomber, and left the building in the suburb of Saint-Denis in a state of near-collapse.

As forensic detectives were combing the rubble for clues, Belgian police carried out raids in and around Brussels in connection with the Paris attacks.

The searches in the Molenbeek and Jette areas of Brussels targeted addresses linked to one of the suicide bombers, Bilal Hadfi, as well as Salah Abdeslam – another of the Paris attackers who is believed to still be on the run.

Underscoring the urgency of the hunt for those linked to the terrorist cell, the French Prime Minister said France could face the risk of chemical or bacterial warfare in its fight against Islamist militants.

"We must not rule anything out. I say it with all the precautions needed. But we know and bear in mind that there is also a risk of chemical or bacteriological weapons," Manuel Valls told parliament. "The macabre imagination of the masterminds is limitless."

Mr Valls' comments came as the head of Europol warned that Europe was likely to face new Islamic State attacks.

"It is reasonable to assume ... that further attacks are likely," Europol director Rob Wainwright told lawmakers in a hearing in the European Parliament in Brussels.

He compared Friday's events in Paris to those in Mumbai in 2008, when militants killed 166 people at different locations.

"This is clearly therefore a more significant and threatening form of terrorism than the phenomenon of the lone actor," he said. "It's also a clear statement of intent by ISIS to export its brutal brand of terrorism to Europe to take it more onto the international stage."

US authorities have warned of potential militant attacks in Italy, whose security services are looking for five possible suspects, Italy's Foreign Minister said.

Speaking to state broadcaster RAI, Paolo Gentiloni referred to "possible terrorist attacks" that could be aimed at St Peter's Basilica in Rome or the cathedral or La Scala theatre in Milan.

The US embassy in Rome said in a message to its citizens that – alongside the big tourist destinations – churches, synagogues, restaurants, theatres and hotels in the country's two main cities could also be targets.

On Wednesday evening, Paris prosecutor Francois Molins confirmed that neither Abaaoud, nor fugitive terror suspect Saleh Abdeslam were among the eight people arrested in the predawn operation.

Police said their investigation had been slowed by the state of the three-storey building - forensic detectives had to be temporarily pulled out when they discovered the walls and floor were collapsing. Engineers were sent in to shore it up to allow work to resume.

At least two people died in the assault, Mr Molins said - one body pulled from the rubble, and a woman who died in an explosion. The "first elements" of the investigation suggested she had triggered an explosive vest, though this had not yet been confirmed.

The other body had been "mutilated by grenades" and wasn't recognisable, police said.

Five police officers were wounded in the attack, and one police dog - seven-year-old Diesel - died after being sent in to scout the building in the assault's early stages.

Mr Molins revealed that the raid had not gone as planned.

The RAID anti-terror unit had set explosives to break down the door of the apartment at 4.30am. However the door had been reinforced and did not immediately give way, allowing the terror cell time to prepare their defence.

BFM TV and RTL radio identified the dead woman as 26-year-old Hasna Aitboulahcen, a cousin of Abdelhamid Abaaoud. She was born in Clichy-la-Garenne in 1989, and worked in the construction industry in Epinay-sur-Seine until 2012.

RTL reported she was seen making a phone call just minutes before dying - which could lead to other accomplices.

And TF1 reported that she had "repeatedly threatened the French government and expressed her desire for jihad".

Police launched the operation after receiving information from tapped phone calls, surveillance and tip-offs suggesting that Abaaoud was holed up in the apartment in Paris' Saint-Denis neighbourhood.

There were several media reports that the cell had been planning a new attack, potentially in Paris' business and financial district La Defense.

The attacks of November 13 left at least 129 dead and more than 350 wounded. France is still in a state of emergency, which the parliament is now debating extending for three months.

As of Wednesday evening security forces had conducted 414 raids across the country, in every major city, made 60 arrests and seized 75 weapons, including a rocket launcher.

Mr Molins said investigators were led to the Saint-Denis apartment by evidence including a mobile phone found in a dustbin outside the Bataclan concert hall, where 89 of the victims of Friday's atrocity died. It contained a text message sent about 20 minutes after the massacre began.

"Let's go, it's started," it read.

Mr Molins said investigators were still trying to identify the recipient of the message.

Investigators are also following links to jihadist Fabien Clain, from Toulouse, whose voice was recognised on an IS recording claiming responsibility for the attacks.

A Spanish security official said on Wednesday that French authorities had sent a bulletin to police across Europe asking them to watch out for a Citroen Xsara car that could be carrying Salah Abdeslam, whose brother, Brahim, was among the attackers who blew themselves up.

Since the bulletin became public it is possible he would have abandoned the car.

French President Francois Hollande, in a speech to the country's gathered mayors, reiterated his claim that France was "at war" with IS, and argued for proposed new laws extending police and security service powers.

Terrorists had attacked the "very idea of France", he said. He warned that IS must not be allowed "to poison us with stigmatisation, fear and division … France will remain the country of freedom".

"Life must go on," he said. "Our duty is to ensure that life goes on."

with Reuters