US special forces snatched a top Al-Qaeda suspect in Libya and stormed a Shebab leader's home in Somalia in daring twin raids, as Washington pledged to do everything possible to track down terror suspects.

In Libya, authorities demanded an explanation of what they called the "kidnap" on Saturday of Abu Anas al-Libi, a long-sought Al-Qaeda operative indicted in connection with the 1998 bombings of US embassies in Kenya and Tanzania.

In Somalia, Prime Minister Abdi Farah Shirdon said its cooperation with foreign partners in the fight on terror was "no secret" after US Navy SEAL commandos stormed the home of a leader of the country's Al-Qaeda-linked Shebab militants in the southern port of Barawe on Saturday.

That raid -- the success of which was still unclear, with the fate of the target uncertain -- came after last month's bloody militant siege of an upscale shopping mall in the Kenyan capital Nairobi that left 67 people dead.

"We hope that this makes clear that the United States of America will never stop in its effort to hold those accountable who conduct acts of terror," Secretary of State John Kerry said Sunday during a visit to the Indonesian island of Bali.

The action should also make clear that "those members of Al-Qaeda and other terrorist organizations literally can run, but they can't hide," said Kerry, speaking during a break from meetings of the Asia-Pacific Economic Cooperation forum.

No US personnel were killed or injured in either operation, officials said. Several Shebab militants were killed in the Somalia raid, one official said.

The Pentagon said Libi was being "lawfully detained under the law of war in a secure location" outside Libya, hailing his capture as a "clear sign" of the US commitment to hunting down those wanted for acts of terror.

Libi, who was on the FBI's most wanted list with a $5 million bounty on his head, had been indicted in US federal court for allegedly playing a key role in the east Africa bombings -- which left more than 200 dead -- and plots to attack US forces, Pentagon spokesman George Little said.

"Wherever possible, our first priority is and always has been to apprehend terrorist suspects, and to preserve the opportunity to elicit valuable intelligence that can help us protect the American people," Little said.

The operation ended a 13-year manhunt for the 49-year-old Libi, whose given name is Nazih Abdul Hamed Al-Raghie.

The US raid took place in broad daylight with the knowledge of the Libyan government, a US official told CNN. A source close to Libi told AFP he was snatched by armed men in Tripoli.

Libya, however, said the raid had no official authorization and demanded answers.

"The Libyan government has been following the reports of the kidnap of one of the Libyan citizens wanted by the authorities in the United States," a government statement said.

"As soon as it heard the reports, the Libyan government contacted the US authorities to demand an explanation."

In Somalia, a US official said a "high-value" Shebab leader was the target.

The operation marked the most significant US assault in Somalia since commandos killed key Al-Qaeda operative Saleh Ali Saleh Nabhan in the same area four years ago.

"US personnel took all necessary precautions to avoid civilian casualties in this operation and disengaged after inflicting some Shebab casualties," the official said.

"We are not in a position to identify those casualties," the official said, adding that "even in these extreme operational circumstances, the US military is very cautious to minimize civilian casualties."

Leaders of the Shebab in Barawe, one of the few ports left in the hands of the insurgents, said commandos attacked from the sea and the air, but failed in their attempt to storm a house belonging to a senior commander.

The SEAL team approached and fired on the unidentified target's seaside villa by sea, according to The New York Times.

Although the Shebab leader was believed to have been killed during the assault, the SEALs had to withdraw before they could confirm the kill, a senior US official told the newspaper.

"The Barawe raid was planned a week and a half ago," a US security official told the Times. "It was prompted by the Westgate attack."

"Our cooperation with international partners on fighting against the terrorism is not a secret," Farah Shirdon said.

"Understand me, that fighting is not a secret. And our interest is to get a peaceful Somalia... free from terrorism and problems."

Shebab spokesman Abdulaziz Abu Musab told AFP that commandos had stormed the beach by boat, but blamed Britain and Turkey.

"The bungled operation was carried out by white people, who came with two small boats from a larger ship out at sea... one Shebab guard was killed, but reinforcements soon came and the foreigners fled," he said.

"Where the foreigners had been, afterwards we saw lots of blood, so maybe we wounded some."