Seven Al-Shabab terrorists were killed in a suicide attack carried out by the terrorist group in the heart of Mogadishu late on Saturday afternoon, the Somali government said on Sunday.

The attack at a detention facility holding some of the terrorists lasted for hours.

"The security forces succeeded in ending the terrorist attack, shooting all seven terrorists who were involved," the Somali interior ministry said in a statement.

A powerful explosion on Saturday afternoon signalled the beginning of the attack, and its shockwaves were felt by an AFP correspondent two kilometres away at the time.

Sporadic gunfire

Reaching the location 30 minutes later, the correspondent heard multiple explosions and intense gunfire exchanges from the Godka Jilicow detention facility.

Godka Jilicow, which is near the presidential palace, often holds Al-Shabab terrorists before they go to trial.

Local residents told AFP they could hear sporadic gunfire for more than three hours after the assault began.

Somalia has fought Al-Shabab terrorists since the mid-2000s.