MOGADISHU (Reuters) - Somali rebels hit the African Union's main base in Mogadishu with two suicide car bombs on Thursday, killing at least nine people and showing their ability to strike at the heart of the peacekeeping mission.
Hospital sources said at least seven more people were killed in artillery battles that broke out afterwards. Burundi's army said the deputy commander of the African Union's (AU) mission AMISOM was among the dead. Uganda said its force commander was wounded.
The insurgents launched the attack after saying they would avenge the killing on Monday of one of the continent's most wanted al Qaeda suspects in a helicopter raid by U.S. commandos.
Witness Farah Hassan said two white U.N.-marked vehicles drove into the coastal military base followed by two pick-up trucks carrying Somali government troops.
"We thought they were real U.N. cars carrying white people, but moments later deafening thunder shook the ground," he told Reuters. "The area was covered with flames and clouds of smoke."
A Reuters reporter saw six wounded soldiers carried away from the site of the blasts, some bleeding heavily.
Among the casualties were civilians who had been receiving medical treatment at the AU base, witnesses said. Senior Somali government officials, including the national police chief, were meeting AMISOM leaders there at the time.
Al Shabaab guerrillas have looted U.N. compounds in recent months, and Somali Information Minister Dahir Mohamud Gelle said the drivers of the two cars were foreign fighters.
"They spoke English and identified themselves as being from the United Nations," he told Reuters.
It looked to be the worst attack on the 5,000-strong force since 11 Burundians were killed in February by two suicide bombers who infiltrated another base. And it followed one of the capital's most violent months in 20 years.
"WE GOT OUR REVENGE"
A suicide bomber killed Somalia's national security minister and at least 30 other people in a strike in June on a central town, again targeting senior officials attending a meeting.
Fighting in Somalia has killed more than 18,000 civilians since the start of 2007 and left 1.5 million more homeless.
Western security agencies say the lawless nation has become a safe haven for militants, including foreign jihadists, who are using it to plot attacks across the region and beyond.
Al Shabaab's spokesman, Sheikh Ali Mohamud Rage, told Reuters that Thursday's attacks were to avenge the death of Kenyan-born Salah Ali Saleh Nabhan, who was killed in rebel-held southern Somalia on Monday by U.S. special forces.
The 28-year-old had been allied with al Shabaab, which Washington accuses of being al Qaeda's proxy in the country.
"We have got our revenge for our brother Nabhan. Two suicide car bombs targeting the AU base, praise Allah," Rage said.
"We knew the infidel government and AU troops planned to attack us after the holy month. This is a message to them."
There were five suicide bombers in the two cars, he added.
Thursday's attack may deter some African nations, including Nigeria and Djibouti, that have agreed in principle to send soldiers to reinforce AMISOM. So far, Uganda and Burundi are the only nations to have sent soldiers.
U.N. Secretary-General Ban Ki-moon said he was shocked and outraged by the attack and that U.N. resources from neighbouring peace operations were ready to help the AU respond.
Hours before the blasts, al Shabaab issued demands in return for the release of a French security consultant they are holding hostage, including an immediate end to French support for the Somali government and the withdrawal of AMISOM troops.
The Frenchman is one of two security consultants seized by gunmen in Mogadishu in July. His colleague escaped on Aug. 26.
(Additional reporting by Abdi Sheikh in Mogadishu, Sahra Abdi and Frank Nyakairu in Nairobi, Patrick Nduwimana in Bujumbura and Patrick Worsnip at the United Nations; Writing by Daniel Wallis; Editing by Angus MacSwan)