* AU team to investigate illness * 18 soldiers in hospital in Nairobi * Heavy fighting kills at least 15 people By Frank Nyakairu NAIROBI, July 23 (Reuters) - Three Burundian peacekeepers based in Somalia have died from an unknown illness and 18 more are in a Kenyan hospital with the same symptoms, an African Union (AU) official said on Thursday. There are some 4,300 soldiers from Burundi and Uganda in Somalia's capital defending key sites and helping government forces fight off regular attacks from hardline insurgents with links to al Qaeda. "The African Union and the Burundian government have dispatched a team of medical experts to ascertain what has caused an illness in a Burundian contingent," said Gaffel Nkolokosa, spokesman for the AU envoy to Somalia. "Twenty-one soldiers were evacuated earlier this week after exhibiting similar symptoms and three of those have since died," he said, declining to speculate on the cause of the illness or what the symptoms were. Somalia's transitional government is hemmed into a few blocks of the capital Mogadishu by rebels bent on toppling President Sheikh Sharif Ahmed and imposing their own harsh version of sharia law throughout the country. Western nations fear that if the al Shabaab group, and the foreign fighters within its ranks, seize control of Somalia, they could destabilise neighbouring countries and train militants to launch attacks elsewhere. While al Shabaab controls much of southern and central Somalia, the presence of AU troops has effectively led to a military stalemate in the capital with neither side able to deliver a knock out blow. At least 15 people were killed and 53 wounded in heavy fighting in three districts of Mogadishu that started late on Wednesday and continued on Thursday morning, according to Ali Muse from the Life Line ambulance service. Residents said the insurgents attacked positions held by government soldiers and AU peacekeepers. An estimated 223,000 people have fled Mogadishu since May 7, when fighting erupted between government troops and al Shabaab. (Additional reporting by Abdi Guled and Abdi Sheikh in Mogadishu, Ibrahim Mohamed in Hargesia; Writing by David Clarke; Editing by Jack Kimball)
A hardline Somali Islamist militant cleans his gun under a tree north of Mogadishu July 21, 2009. Intense fighting is making it increasingly difficult to deliver aid to Somalia, where it ...
