MOGADISHU (AFP) - Mortar attacks by Somali rebels disrupted a parliamentary session Monday as heavy fighting between the militia and African Union-backed government forces killed seven civilians, officials said. The parliament was meeting for the first time since the hardline Shebab and Hizb al-Islam militias launched an anti-government offensive in May. Several mortar shells struck the compound where we were having a session but there were no casualties. The session was called off after the attack and will continue tomorrow, lawmaker Mohamed Adan told AFP. Some 300 MPs were meeting in a building in the south of the capital Mogadishu when Shebab militants began firing mortars. We heard explosions of mortar as we started our session minutes after the president left the compound, said Hussein Ali, another lawmaker. At least seven civilians were killed and 18 others wounded in fighting between the Shebab and government forces backed by the AU troops, police in the capital said. Police commander Mohamed Yusuf said the insurgents attacked their positions in the south of the war-riven city. Seven civilians were killed in the crossfire and by stray mortars that struck civilian residential areas, Yusuf said. Mogadishu has been ravaged by years of violence that worsened two months ago when the insurgents stepped up an offensive against the internationally-backed government of President Sharif Sheikh Ahmed.