TRIPOLI (REUTERS) - Two commando raids in Africa show the United States is pressuring Al-Qaeda, officials said on Sunday, though a failure in Somalia and an angry response in Libya also highlighted Washington's problems.

In Tripoli, US forces snatched a Libyan wanted over the bombings of the US embassy in Nairobi 15 years ago and whisked him out of the country, prompting Secretary of State John Kerry to declare that Al-Qaeda leaders "can run but they can't hide".

However, the capture of Nazih al-Ragye, better known as Abu Anas al-Liby, also provoked a complaint about the "kidnap" from the Western-backed prime minister; he faces a backlash from armed Islamists who have carved out a share of power since the West helped Libyan rebels oust Muammar Gaddafi two years ago.

In Somalia, Navy Seals stormed ashore into the Al-Shabaab stronghold of Barawe in response to the attack last month on a Kenyan mall but, a US official said, they failed to capture or kill the unnamed target among the Somali allies of Al-Qaeda.

Mr Kerry, on a visit to Indonesia, said President Barack Obama's administration was "pleased with the results" of the combined assaults early on Saturday. "We hope this makes clear that the United States of America will never stop in its effort to hold those accountable who conduct acts of terror," he said.

Two years after Navy Seals finally tracked down and killed Al-Qaeda founder Osama bin Laden in Pakistan, a decade after Al-Qaeda's Sept 11 attacks on the United States in 2001, the twin operation demonstrated the reach of US military forces in Africa, where Islamist militancy has been in the ascendant.

However, the forays also threw a spotlight on how Somalia remains a fragmented haven for Al-Qaeda allies more than 20 years after Washington intervened in vain in its civil war and on how Libya has descended into an anarchic battleground on the Mediterranean that stretches deep south into the Sahara.

Disrupting the organisation of its most aggressive enemy in an oil-rich state that is awash with arms and sits on Europe's doorstep may have been more the priority in seizing Liby than putting on trial a little-known suspect in the 1998 bombings of the US embassies in Kenya and Tanzania that killed 224 people.

One Libyan security official, himself a former commander of Islamist rebels against Gaddafi, warned that Al-Qaeda and its allies would prepare a violent response to the snatching of Liby as he returned to his suburban home from dawn prayers.

Clearly aware of the risks to his government of complicity in the US raid, Prime Minister Ali Zeidan said in a statement:"The Libyan government is following the news of the kidnapping of a Libyan citizen who is wanted by US authorities. The Libyan government has contacted US authorities to ask them to provide an explanation."

Mr Abdul Bassit Haroun, a former Islamist militia commander who works with the Libyan government on security, said the US raid would show Libya was no refuge for "international terrorists".

"But it is also very bad that no state institutions had the slightest information about this process, nor do they have a force which was able to capture him," he told Reuters. "This means the Libyan state simply does not exist."

He warned that Islamist militants, like those blamed for the fatal attack on the US consulate in Benghazi a year ago, would hit back violently.

"This won't just pass," he said. "There will be a strong reaction in order to take revenge because this is one of the most important Al-Qaeda figures."

Somalia's Western-backed government said it did cooperate with Washington, though its control of much of the country, including the port of Barawe, just 180km south of the capital Mogadishu, is limited by powerful armed groups.

"We have collaboration with the world and with neighbouring countries in the battle against Al-Shabaab," Prime Minister Abdi Farah Shirdon said when asked of Somalia's role in the raid.

US forces have used airborne drones to kill Somalis in the past and last year Seals freed two kidnapped aid workers there.

Somali police said seven people were killed in Barawe. US officials said their forces took no casualties but had broken off the fighting to avoid harming civilians. They failed to capture or kill their target during fighting around dawn at a seaside villa that Al-Shabaab said was one of its bases.

A Somali intelligence official said a Chechen commander, who might have been the Americans' target, was wounded.

In Somalia, Al-Shabaab spokesman Sheikh Abdiasis Abu Musab told Reuters no senior figure was present when the Americans came ashore. He said: "Ordinary fighters lived in the house and they bravely counter-attacked and chased off the attackers."

A US official was quoted as saying the raid was planned in response to the Westgate mall attack by Al-Shabaab gunmen in which at least 67 died last month. The group said it was hitting back at Kenyan intervention in Somalia, which has forced it from much of its territory. It also targeted Westerners out shopping.

From Nigeria in the west, through Mali, Algeria and Libya to Somalia and Kenya in the east, Africa has seen major attacks on its own people and on Western economic interests, including an Algerian desert gas plant in January and the Nairobi mall as well as the killing of the US ambassador in Libya a year ago.

The trend reflects a number of factors, including Western efforts to force Al-Qaeda from its former base in Afghanistan, the overthrow of anti-Islamist authoritarian rulers in the Arab Spring of 2011 and growing resentment among Africa's poor with governments they view as corrupt pawns of Western powers.

Western intelligence experts say there is evidence of growing links among Islamist militants across northern Africa, who share Al-Qaeda's goal of a strict Islamic state and the expulsion of Western interests from Muslim lands.

Liby, who has been reported as having fled Gaddafi's police state to join bin Laden in Sudan in the 1990s before securing political asylum in Britain, may have been part of that bid to consolidate an operational base, analysts say.

Wanted by the FBI, which gives his age as 49 and had offered a $5 million reward for help in capturing him, Liby was indicted in 2000 along with 20 other Al-Qaeda suspects including bin Laden and current global leader Ayman al-Zawahri.

Charges relating to him personally accused him of discussing the bombing of the Nairobi embassy in retaliation for the US

intervention in the Somali civil war in 1992-93 and of helping reconnoitre and plan the attack in the years before 1998.

Obama, wrestling with the legal and political difficulties posed by prisoners at the US military base at Guantanamo Bay in Cuba, has said he does not want to send more suspects there.

But a spokeswoman for the White House National Security Council said it was still not decided where Liby would be tried.

His indictment was filed in New York, making that a possible venue for a civilian, rather than military, trial. It was unclear where Liby was on Sunday.