* Investigating use of cars in suicide blasts * Warns attack will hinder aid deliveries * President Ahmed says undeterred by bombings (Adds quote, details, paragraphs 9-10) By Frank Nyakairu NAIROBI, Sept 19 (Reuters) - The United Nations is investigating the use of its vehicles by suicide bombers who killed 17 African Union peacekeepers at their main base in Somalia, a senior official said on Saturday. The Somali government warned on Friday that Islamist rebels from the al Shabaab group had six more stolen U.N. cars primed with explosives ready for suicide attacks. [ID:nLI195515] "There are very large numbers of U.N. vehicles in Somalia that have been used for a variety of projects," Mark Bowden, the U.N. humanitarian coordinator for Somalia, told Reuters. He said the United Nations had been given the chassis number of one of the vehicles used in Thursday's blasts. "We are trying to trace whether it's a U.N. vehicle," Bowden added. President Sheikh Sharif Ahmed said the attack, which followed Monday's killing of one of Africa's most wanted al Qaeda suspects by U.S. special forces, would not deter his government and he called on the world to send it more help. "The bombing was shocking ... I urge the world to assist the starving Somali people," Ahmed told reporters in a news conference at his hilltop Villa Somalia palace on Saturday. He said his administration had given Washington permission to hunt down Saleh Ali Saleh Nabhan -- a 28-year-old Kenyan wanted over the 2002 truck bombing of an Israeli-owned hotel in Kenya that killed 15 people -- because it could not catch him. U.N. PRECAUTIONS Insurgents overran U.N. compounds in Jowhar and Baidoa in May and July, looting supplies and stealing vehicles. That has prompted speculation the cars used in the suicide attacks were seized then, but Bowden raised the possibility that the vehicles could have come from further afield. "Depending on the marking, they could have been vehicles that have been brought in from the Eritrean peacekeeping operation, or they are vehicles that have been used on projects over the years," he said. Bowden said this week's attack on the AMISOM peacekeepers' heavily-guarded base by Mogadishu airport would not weaken the U.N.'s resolve to deliver aid to half the Somali population. But he said it could hinder operations on the ground. "We have to take greater precautions around Mogadishu. Clearly the airport is more at risk and that will affect our ability to move staff and humanitarian goods," he said. The al Shabaab rebel group, which Washington says is al Qaeda's proxy in the failed Horn of Africa state, controls much of the south and parts of the capital. Together with another group Hizbul Islam, it has been fighting government troops and the AU peacekeepers to impose its own strict version of sharia law throughout Somalia. On Saturday, al Shabaab gunmen ordered traders at Mogadishu's sprawling Bakara Market to join their fight or quit their stalls, businessmen said. The rebels also demanded they contribute financially or in kind to their cause. More than 18,000 Somalis have been killed in fighting since the start of 2007 and another 1.5 million left homeless. Bowden said severe drought for the fifth year in a row had compounded the effects of rising violence and driven half the population into food aid dependence. (Additional reporting by Ahmed Mohamed and Abdi Guled in Mogadishu; Writing by Duncan Miriri; Editing by Daniel Wallis and Matthew Jones)
Somalia's President Sheikh Sharif Ahmed addresses a news conference in Mogadishu, September 19, 2009. The United Nations is investigating the use of its vehicles by suicide bombers who killed 17 African ...
