MOGADISHU, Somalia -- At least three mortars landed inside Somalia's heavily fortified presidential palace compound on Thursday, a Somali police officer said.

Some were wounded in the attack that was claimed by Somali Islamic extremist group al-Shabab through the group's radio station, Andulus.

Somalia's security ministry said that the mortars were mostly aimed at terrorizing the public. There was no immediate information on whether there were deaths from the attack.

Some people were injured.

Somali officials sometimes use the term "superficial" when referring to mortar attacks by al-Shabab in Mogadishu that don't cause much damage.

Two more mortars struck a residential area near the state house which houses Somali president, prime minister and speaker of the parliament, said police officer Capt. Mohamed Hussein.

Despite major setbacks in 2014, al-Shabab continues to wage a deadly insurgency against Somalia's government and remains a threat in Somalia and the East African region. The group has carried out many attacks in Somalia and in neighbouring countries, including Kenya, whose armies are part of the African Union troops bolstering Somalia's weak U.N.-backed government.

Al-Shabab controlled much of Mogadishu during the years 2007 to 2011, but was pushed out of Somalia's capital and other major cities by African Union forces.