At least five  people were killed when a salvo of mortars targeting Somalia's  presidential palace missed and landed on a nearby refugee camp  overnight, residents and the African Union's peacekeeping force said on  Monday.

Somalia's al Qaeda-aligned al  Shabaab rebel group said they fired more than a dozen mortars at the  heavily fortified presidential compound, their second attempt to strike  at the heart of the embattled government in less than a week.

Paddy Ankunda, spokesman for the AU force known as AMISOM, said some mortar  rounds crashed into a camp for Somalis displaced by war and famine about 500 meters from the presidential palace.

"No mortar landed in the palace - they landed on an IDP camp and killed about six civilians," Ankunda told Reuters.

Mogadishu resident Ali Hussein, who lives next to the squalid settlement, said  one mortar killed five members of a single family.

Ankunda said it was not clear where the short-range mortars were fired from.  Villa Somalia, as the presidential compound is known, is normally beyond the range of mortars launched from outside the Somali capital.

The militants did not disclose their firing point, but a location within  Mogadishu would embarrass AMISOM and the government, which last week  claimed they had secured all of Mogadishu.

While al Shabaab pulled out of the capital in August and African Union forces have been securing neighborhoods vacated by the Islamist rebels, the  coastal city remains prone to regular attacks by suicide bombers and  roadside explosions.

"See how we  are serious," said Sheikh Abdiasis Abu Musab, the spokesman for al  Shabaab's military operation. "We shall continue attacking the palace  with suicide bombings and shells."

In a separate incident, al Shabaab attacked a building housing security  forces in Mogadishu's Alikamin area, between Bakara market and Mogadishu stadium.

"We attacked security  forces in a house. We killed them and destroyed the building with  rocket-propelled grenades and machine gun fire last night," Sheikh  Mohamed Abu Abdirahman, who the militants' refer to as the governor of  Mogadishu, said.

Residents reported heavy gunfire in the area overnight but could not confirm casualties.

Source: Reuters