Residents near a refugee camp in Somalia's capital said Monday that mortars landed on the camp overnight, killing a father and a son and wounding seven others.

The mortar barrage is the third such attack in Mogadishu over the last week. Even though al-Shabab militants have largely been pushed out of the capital, the attacks show the security situation is still tenuous.

Muhudin Haji, a resident of Mogadishu, said Monday that a man and his son were killed in the overnight attack. The loud blasts were followed by screams from adults and tears from children.

The refugees live near the presidential palace, the likely target of the attack. Nadifo Abdi said some of the seven wounded people lost large amounts of blood.

Al-Shabab has been pushed out of the capital and now faces attack on three sides -- from the African Union force in Mogadishu, Kenyan troops in Somalia's south, and Ethiopian troops in the west.

Ethiopian troops and moderate Islamist fighters seized a town Monday formerly controlled by al-Shabab, residents said. The town, Elbur, is about 225 miles north of Mogadishu.

"Al-Shabab fighters have already fled and Ethiopian soldiers and tanks are here now," resident Mohamed Mursal said by phone. "They are searching homes now and manned roadblocks. People are staying inside out of fear."

Al-Shabab said in a statement that it fled the town as a "tactical retreat."

Elbur was the militants' largest stronghold in central Somalia. It served as a weapons depot and training center.