* U.S. raid could win valuable intelligence

* Attack could inflame anti-Western opinion

* Lack of civilian casualties seen as boost for military

LONDON, Sept 15 (Reuters) - A U.S. raid in Somalia that killed one of Africa's top al Qaeda men has likely won valuable counter-terrorism intelligence but risks further inflaming anti-Western opinion in a country of growing concern.

The apparent absence of civilian casualties in Monday's strike, in which U.S. special forces took custody of the body of the man, Saleh Ali Saleh Nabhan, is a notable win for military anti-terror efforts often condemned for killings of innocents.

Nabhan's body also represents a rare intelligence find for a campaign that often uses missiles fired from remotely operated drones and that as a result is sometimes hampered, most notably in Pakistan, by uncertainty about who exactly has been killed.

"Even dead, this individual is an intelligence gold mine," said Nick Pratt, a retired U.S. Colonel and Professor of Strategy and International Politics at the Marshall Center in Germany.

"You pick up the body and there's no speculation about whether he's alive or dead. With a drone you can't do that."

"You also want to see who this fellow's been travelling with, and you want to pick up what I call any pocket litter -- his pack, his gear, any computers."

WORRIES ABOUT REVENGE

The Kenyan was killed by U.S. special forces in helicopters operating from a U.S. Navy ship who struck a car in the rebel-held south of the failed Horn of Africa state.

Nabhan is said to have built the truck bomb that claimed 15 lives at an Israeli-owned beach hotel on the Kenyan coast in 2002. He was also accused of involvement in a simultaneous but failed missile attack on an Israeli airliner in Kenya.

Several senior Somali government sources said he had been killed along with four other foreign members of al Shabaab, a group of armed Islamists fighting the fragile government.

But experts said the mere presence of U.S. troops in a war-shattered Muslim country with a disastrous record of Western intervention could hand political ammunition to Shabaab.

"There are mixed feelings," said a Somali civic activist who declined to be identified for security reasons.

"On the one hand, people are relieved. It happened in an isolated place with very little damage or killing of innocents," he told Reuters. "And no one is crying about the loss of individuals who are not Somali.

"But the idea that the Americans can come and kill whoever they want anytime, can this increase radicalisation? People worry about revenge. The next few days will show."

Al Shabaab responded angrily to Nabhan's death, saying it would continue to target America. But a rival militia opposed to al Shabaab welcomed the strike and called for more.

Somalia's U.N.-backed government faces a stubborn insurgency mounted by al Shabaab even as the country suffers one of the world's worst aid emergencies. The rebels have been joined by foreign militants who Western security agencies say are using the country as a haven to plot attacks in the region and beyond.

There are also fears about possible repercussions on Western hostages in Somalia including a French security adviser, a Canadian reporter and an Australian photographer.

"It's contentious and potentially escalatory," Justin Crump, head of terrorism and country risk at the Stirling Assynt security consultancy, said of Monday's raid.

He said experts were on alert for signs that the raid would "stir up a hornet's nest" and lead to plans to avenge Nabhan's death in attacks in the wider east African region.

COUNTER-TERROR MOMENTUM

However, the upside of the raid for Western nations is many-faceted. Apart from the intelligence haul including Nabhan's DNA, it generates politically important momentum to U.S. anti-terror efforts by building on other recent killings of al Qaeda leaders in Pakistan over the past two years.

It may also raise U.S. military morale regarding a country most Americans would rather forget.

Americans remember with a shudder the disastrous U.S.-UN intervention there in the early 1990s, including the infamous Black Hawk Down battle of 1993 when 18 U.S. troops were killed in a 17-hour fire fight that was later made into a hit movie.

James Burnell-Nugent, former commander in chief of the British navy, told Reuters the raid's lack of civilian deaths and the recovery of DNA were "really, really important".

"The global reach of maritime forces gives you the opportunity to carry out surgical operations using maritime troops that minimise the risk of civilian casualties," he said.

Lack of DNA evidence after drone attacks in Pakistan has sometimes led to inconclusive results. One example is Rashid Rauf, suspected ringleader of a 2006 plot to blow up airliners over the Atlantic, who was reportedly killed by a drone attack in Pakistan in 2008. Some commentators question those reports. (Editing by Giles Elgood)