A blast the first of several was heard Wednesday night at the site of where the man suspected of killing seven people in Toulouse is holed up.
Despite reports that a police assault had been launched to try to capture 23-year-old Mohamed Merah, the stand-off has continued.
The explosions were apparently the beginning of an operation to put pressure on Merah to give himself up.
The French elite RAID squad is reluctant to enter the apartment, not knowing if Merah, who is said to be a bomb maker has done just that.
It was early on Wednesday morning that police surrounded Merah’s block after two officers were shot at when they tried to get into his flat.
Following leads including an email trace and a suspicious garage owner, police found a car parked nearby loaded with weapons.
During negotiations Merah has claimed he was responsible for the killing of a rabbi and three children at a Jewish school on Monday and of the murders of three soldiers. He has also said he has links with al Qaeda.
The French authorities say Merah was planning further attacks as the police net closed in around him.