Somali Islamist militants said they fired mortar shells at the presidential palace in the capital, Mogadishu, in an attack that witnesses said damaged vehicles and buildings.

The shells landed "in the vicinity" of President Hassan Sheikh Mohamoud's residence and caused no casualties, Somalia's security ministry spokesman, Mohamed Yusuf, said by phone. Agence France-Presse reported that one guard was killed in the attack, citing a security official.

Adan Doy, a local resident, said he saw "at least five mortar rounds" that caused some damage to surrounding buildings. Police officer Mohamed Elmi said he ran for cover and saw "several vehicles" destroyed by mortar hits.

Militant group al-Shabaab claimed responsibility for the assault in a statement to Radio Andalus, a broadcaster that supports the insurgents.

The al-Qaida-linked group has waged an insurgency in the Horn of Africa nation since 2006 in a bid to impose Islamic law. While the group has lost ground since being driven out of Mogadishu in 2011 by government and African Union forces, it continues to stage deadly gun and bomb attacks.