Saint Denis raid
French soldiers secure the area as shots are exchanged in Saint-DenisREUTERS/Jacky Naegelen

For seven hours a battle raged in Paris' northern suburb of Saint-Denis as police moved in to take out the mastermind of the Paris attacks, Belgian-born Islamic State (Isis) militant Abdelhamid Abaaoud.

Paris prosecutor François Molins said 5,000 rounds of ammunition were expended over the course of the raids against two properties in the area, detailing a deadly confrontation in which five members of Special Forces were injured, two suspects killed and eight more arrested.

Molins praised the efforts of the French police as "rigorous and courageous", explaining that in four days they had carried out two raids that had placed their life in peril, using assault rifles, sniper teams and combat grenades.

The prosecutor said following the chaos of the raids at least one suspect's body had been so badly damaged, forensic tests would be required before he was identified.

Collecting evidence at the apartment building where the worst of the fighting took place has become dangerous for investigators after a floor gave way during the exchanges. The structural damage is believed to have been caused when a woman, identified in reports as Abaaoud's cousin, exploded a suicide vest.

Paris siege: Watch police and army raid Saint-Denis for Isis terror suspectsIBTimes UK

Molins described the discovery of a "proper arsenal of weapons" that included Kalashnikovs, hundreds of rounds of ammunition and suicide vests. He described the terrorist network uncovered by police as "ready to act". They were tipped off to Abaaoud's continued presence in Europe – he was previously believed to be in Syria – on 17 November after telephone surveillance collected appeared to indicate his whereabouts.

Abaaoud's own location remains unclear. Reports published in the Washington Post, citing two senior European intelligence officials, indicate that he was one of those killed in the raids. The French prosecutor would only go as far to say, however, that Abaaoud had not been one of those arrested. He added that Salah Abdeslam, the eighth Jihadist known to have carried out the Paris attacks was, also not among those arrested.

At the press conference Molins outlined the scale of the logistical operation undertaken by the IS militants. He said they had arrived in three separate cars, rented by Salah and Brahim Abdeslam from Belgium, virtually simultaneously and that they had stayed in three separate safe houses.

He added a key piece of evidence collected by French police had been a mobile phone recovered from a bin outside the Bataclan concert hall, where 87 were murdered in the 13 November attacks. A message was sent presumably just before it was tossed stating chillingly: "We've gone, we've started."