Gunfire rang out and explosions were heard as police special forces stormed an apartment building in southern France on Thursday in an attempt to capture an al Qaeda-inspired gunman who has killed seven people, witnesses and officials said.

Assault rifle and lighter calibre gunfire rang out for around four minutes, and explosions were also heard, as special forces sought to capture Mohamed Merah, and an official said that gas was also used to try and paralyse him.

They are in the apartment, they are using gas to try to paralyse him, said Nicole Yardeni, local head of Jewish umbrella group CRIF, in contact with security officials, shortly before the gunfire was heard by Reuters witnesses.

Police entered the five-story building in mid-morning following a standoff of around 30 hours.

(Reporting by John Irish; Writing by Catherine Bremer; Editing by Paul Taylor)