TOULOUSE, France - French police fired shots and set off explosives roughly every hour outside an apartment block in southern France on Thursday to try to force out a 24-year-old gunman suspected of killing seven people, including three Jewish school children and a rabbi, in the name of al-Qaida.Some 27 hours after 300 police first surrounded the five-story building in a suburb of the prosperous industrial city of Toulouse, Mohamed Merah, a French citizen of Algerian origin, was refusing to give himself up. Instead Merah boasted to police negotiators that he had brought France to its knees and said his only regret was not having been able to carry out plans for more killings.He has told negotiators that he killed three soldiers last week and a rabbi and three children at a Jewish school on Monday to avenge the deaths of Palestinian children and because of French army involvement in Afghanistan. He filmed the school shootings using a camera strapped to him.French President Nicolas Sarkozy, whose handling of the crisis may influence voters less than five weeks from an election in which he is running for a second term, promised on Wednesday that justice would be done and asked people not to take vengeance.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.They continued to fire shots roughly every hour, and stepped up the pace at dawn with two loud explosions that sounded like grenades. Analysts said police were attempting to exhaust the gunman and make him easier to capture unharmed."These were moves to intimidate the gunman who seems to have changed his mind and does not want to surrender," said French Interior Ministry spokesman Pierre-Henry Brandet.A dozen bystanders mingled with reporters kept by police at a distance of around 600 meters from the building.Merah, who authorities say has a weapons cache in the apartment including an Uzi and a Kalashnikov assault rifle, wounded two officers on Wednesday."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," French Defense Minister Gerard Longuet told TF1 television.Bringing 'France to its knees'Merah, who told police negotiators he had accepted a mission from al-Qaida after receiving training in the lawless border area of Pakistan, had identified another soldier and two police officers he wanted to kill, investigators said on Wednesday. "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.At a ceremony in an army barracks in Montauban, near Toulouse, Sarkozy paid tribute to the three soldiers of North African origin killed last week."This man wanted to bring the Republic to its knees. The Republic did not give in, the Republic did not back down," he said, standing before three coffins draped in the French flag.Vowing justice, he said the men had been killed in a "terrorist execution". Merah had staked out the first soldier he killed after replying to an advert about a scooter, investigators said.The raid came just three days after the school attack and followed an unprecedented manhunt by French security forces.Merah's lawyer Christian Etelin, who has defended him in several minor crimes, said that his client had a tendency towards violence that had worsened after a stay in prison and trips to Afghanistan and Pakistan."There was his religious engagement, an increasing hatred against the values of a democratic society and a desire to impose what he believes is truth," Etelin told France 2 television.