Three blasts were heard at the site of the house of the man suspected of killing a teacher and three children at a Jewish school and three soldiers.
The man has been holed up in a Toulouse apartment block surrounded by police for almost 21 hours. Each blast was accompanied by an orange light.
French special forces, which encircled the building complex at 3:00 a.m. today, were told by the 23-year-old man that he may give himself up this evening, Francois Molins, the Paris state prosecutor overseeing the investigation, had said at a press conference.
As night fell, the area around the building was plunged into darkness with all lights turned out. The suspect, Mohammed Merah, is a French national of Algerian descent, who claims to have ties to al-Qaeda and spent time on the Afghanistan-Pakistan border.