TOULOUSE/PARIS, France - French police tried to flush out a 24-year-old gunman suspected of killing seven people in the name of al Qaeda, with explosions and gunfire heard outside his apartment on the second day of a siege in the southern French city of Toulouse.

In a drama gripping France five weeks before a presidential election, some 300 police have laid siege since Wednesday to the five-storey house in a suburb of the prosperous industrial town in a bid to capture the shooter, Mohamed Merah.

The French citizen of Algerian origin told negotiators he had killed three soldiers last week and four people at a Jewish school in Toulouse on Monday to avenge the deaths of Palestinian children and because of French army involvement in Afghanistan.

An undated and non-datelined video frame grab broadcast March 21, 2012 by French national television station France 2 who they claim to show Mohamed Merah. [Photo/Agencies]

France's elite RAID commando unit detonated three explosions just before midnight on Wednesday, flattening the main door of the building and blowing a hole in the wall, after it became clear Merah did not mean to keep a promise to turn himself in.

"These were moves to intimidate the gunman who seems to have changed his mind and does not want to surrender," ministry spokesman Pierre-Henry Brandet told Reuters.  

Another explosion and several gunshots were heard in the early hours of Thursday morning.

Merah, who authorities say has a weapons cache in the apartment including an Uzi and a Kalashnikov assault rifle, wounded two officers when in the early morning raid.

"What we want is to capture him alive, so that we can bring him to justice, know his motivations and hopefully find out who were his accomplices, if there were any," Defence Minister Gerard Longuet said on TF1 television.

Thomas Withington at London's Centre for Defence Studies said police might wait until just before dawn before launching an assault after throwing a stun grenade into the house.

"What complicates things is that they want to take him alive. They want to wait until he gets very tired," he said.

Merah, who has told police negotiators he had accepted a mission from al Qaeda after receiving training in the border area of Pakistan, had already identified another soldier and two police officers he wished to kill, investigators said.

"He has no regrets, except not having more time to kill more people and he boasts that he has brought France to its knees,"  

Paris Prosecutor Francois Molins, part of the anti-terrorist unit leading the investigation, told a news conference.

The gunman negotiated with police all Wednesday, promising to give himself up and saying that he did not want to die.

"He's explained that he's not suicidal, he doesn't have the soul of a martyr and he prefers to kill but to stay alive himself," the prosecutor said.