MOGADISHU, Somalia (AP) — Witnesses say al-Qaida-linked extremists have stormed a regional government office in Somalia’s capital.

The founder of the Aamin ambulance service told The Associated Press his team has collected at least 16 wounded people from the scene of Sunday’s attack. “So far, we haven’t yet collected any dead people, although the gunshots are still ongoing,” Abdulkadir Adan said.

The al-Shabab extremist group claimed responsibility for the assault on the Banadir Regional Administration headquarters in Mogadishu.

A staff member at the headquarters said the attack began with a suicide bombing before gunmen entered and exchanged fire with security guards. The staffer, Mustafa Abdulle, said most of the workers were rescued by security forces.

Al-Shabab often carries out attacks in Mogadishu. The federal government last year declared “total war” on the extremist group and has retaken a number of communities the fighters had controlled in central and southern Somalia.