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, Reuters reported.
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.