MOGADISHU - Artillery shells killed at least 11 people in the Somali capital Mogadishu on Thursday after rebels fired mortar bombs at the presidential palace and guards there returned fire, witnesses said.

Heavy fighting regularly rocks the port city, where the Western-backed government controls little more than the palace, the airport, sea port and a few streets in between.

Residents said Islamist rebels opened fire on the hilltop Villa Somalia palace, prompting a volley of shells in return that mostly struck the Yaqshid district of northern Mogadishu.

We have so far collected 11 dead bodies and 34 people who were injured in the shelling, Ali Muse, coordinator of the city's ambulance service, told Reuters by telephone.

All these people were injured or killed in various districts in the north of Mogadishu. The death toll may rise because the shelling is still going on sporadically.

Somalia has had no central government for 18 years, and efforts to install one have been undermined by an insurgency led by the al Shabaab rebel group, which Washington accuses of being al Qaeda's proxy in the failed Horn of Africa state.

Fighting has killed 19,000 Somalis since the start of 2007 and driven another 1.5 million from their homes, triggering one of the world's worst humanitarian emergencies.

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