UN warns of 'imminent' attack on Somali rebel bastion

The United Nations warned Tuesday of an impending assault on the southern Somali port of Kismayo, the largest remaining stronghold of the country's Al-Qaeda linked Shebab insurgents. "Fighting for control of the town appears imminent," said Mark Bowden, the top UN humanitarian aid official for the war-torn nation, noting reports of recent naval artillery bombardment as well as air strikes. African Union troops, Ethiopian forces and various Somali militia forces have wrested a string of towns from the hardline Shebab, with the capture of Kismayo -- a crucial revenue source for the fighters -- seen as a key target. Last week Shebab officials and residents said three civilians were killed by missile strikes on the port, reportedly by a naval barrage from an unidentified ship. Several foreign navies operate anti-piracy patrols off the coast of the Horn of Africa nation, including European, US, Russian and Chinese forces. Neighbouring Kenya has smaller vessels operating offshore from Kisamayo, supporting its ground troops, who invaded southern Somalia last year, before joining the nearly 17,000-strong AU force. "I am deeply concerned by recent reports of civilian casualties in Kismayo caused by naval gunfire and airstrikes," Bowden said. "I reiterate my call for all parties to the conflict to make every effort to minimise the impact of conflict on civilians, and to allow full humanitarian access to all people in need," Bowden added in a statement. The reports of the long-awaited assault come as the corruption-riddled government wraps up eight years of infighting, with a UN-backed selection process for new leaders due to be completed by an August 20 deadline. Three Ugandan army helicopters en route to Somalia to support the AU force crashed in Kenya on Sunday leaving at least two soldiers dead. The deployment would have greatly aided forces ahead of any assault on Kismayo.