By Mohamed Ahmed
BAIDOA, Somalia, Oct 20 (Reuters) - A regional official in Somalia accused Islamist rebels on Monday of killing a U.N. employee in the second assassination of a senior aid worker in two days in the lawless Horn of Africa nation.
Unidentified gunmen shot dead Muktar Mohammed Hassan, a local man working for the United Nations Children's Fund (UNICEF), in the southern town of Hudur on Sunday.
The killing came just 48 hours after a U.N. World Food Programme official was killed in a similar attack as he left a mosque in the central town of Merka.
Mohamed Maalim, the chairman of Hudur, said Islamist insurgents from the al Shabaab group were controlling the town.
"We are sure al Shabaab killed him," Maalim told Reuters.
"They previously looted the property of the International Medical Corps and also killed other aid workers in the region."
Shabaab leaders could not immediately be reached.
The rebels have been fighting Somalia's interim government and its Ethiopian military allies since the start of last year. The violence has killed nearly 10,000 civilians and driven more than a million from their homes.
Combined with a severe drought, the bloodshed has triggered what aid agencies call Africa's most acute humanitarian crisis.
In August, an authoritative study showed the number of Somalis needing aid had leapt 77 percent since January to more than 3.2 million people, or more than a third of the population.
UNICEF said Hassan was a technical supervisor on water, sanitation and hygiene projects in Central and Southern Somalia.
"The U.N. reiterates its appeal for an end to acts of violence against humanitarian workers and again calls for safe access for our staff in order to support Somalis who are already living under extremely difficult circumstances," UNICEF Deputy Representative Hannan Sulieman said in a statement.
Suspicion for the assassination of aid workers normally falls on the insurgents or clan militia who are also fighting the interim administration and Ethiopian forces.
The Islamists deny it and instead accuse government hardliners of ordering the killings to discredit the rebels and provoke the international community into sending a robust U.N. peacekeeping force that could help it fend off the insurgents.
Al Shabaab was the military wing of a sharia courts group that ruled much of southern Somalia for six months in late 2006, before being driven out of the capital Mogadishu by government soldiers backed by Ethiopian tanks, troops and fighter planes.
The United States formally listed Shabaab as a foreign terrorist organisation earlier this year and accuses the group of having close ties to Osama bin Laden's al Qaeda network.
(Additional reporting and writing by Daniel Wallis in Nairobi)