Somali armed group al-Shabab has claimed responsibility for an attack on a military compound in Mogadishu where Somali intelligence officials train, claiming it killed "many intelligence forces".

"We captured the building and we are fighting inside it," Sheikh Abdiasis Abu Musab, al-Shabab's military operations spokesman, told Reuters news agency on Sunday.

Somali government sources told Al Jazeera that they regained control of the compound after foiling an attempt by the armed group to break into it.

They said a car bomb was destroyed before it reached the compound and four al-Shabab fighters had been killed. There were no victims among security forces, the government sources said.