Security forces foiled an attempted suicide attack by Islamist militants on a political conference in central Somalia on Thursday, killing three gunmen and the driver of a car packed with explosives, police said.

The al Shabaab group, which frequently attacks officials, politicians and lawmakers in its bid to topple the Western-backed government in Mogadishu, claimed responsibility.

Al Shabaab’s spokesman for military operations, Sheikh Abdiasis Abu Musab, told Reuters shortly after the attack that its gunmen were still fighting inside. Officials denied this. “A suicide car bomb rammed into the gate of the hall and three armed men stormed in but, fortunately, AMISOM troops killed them before they could enter,” said Major Nur Ahmed, a police officer, referring to the African Union force AMISOM guarding the conference hall in the town of Adado.

Local leader Hussein Farah said there was a brief fight but the gunmen were killed before entering the hall, where a meeting for a new central region administration was being held. Somalia, which was torn apart by more than two decades of conflict and clan rivalries, is working on building a new federal structure to restore order to the nation.

The hall was guarded by Somali soldiers and Ethiopian troops, part of the AMISOM force. Police and other officials said the car exploded just outside the gate after the soldiers spotted it and fired at it.

The three gunmen who had tried to storm in were shot dead, they said. AMISOM and the Somali army launched a major offensive last year, pushing al Shabaab out of major urban strongholds, but the group still controls some rural areas from where the group has launched attacks inside Somalia and on neighboring Kenya,