The Libyan prime minister's kidnapping by ex-rebel militiamen on Thursday underlined the state's impotence faced with a myriad of armed groups which in theory take their orders from the authorities.

Gunmen snatched Ali Zeidan from the Tripoli hotel which for security reasons has served as his residence for the past several months, before he was freed several hours later.

U.N. Secretary-General Ban Ki-moon on Thursday condemned the abduction of Libyan Prime Minister Ali Zeidan and said he hoped that reports of his release were true.

"I condemn this abduction in the strongest possible terms," Ban said in Brunei after the end of an Asian regional summit.

British Foreign Secretary William Hague called Thursday for the immediate release of Libyan Prime Minister Ali Zeidan on Thursday after he was seized by gunmen from a hotel in Tripoli.

"I condemn the abduction of the Libyan prime minister in Tripoli this morning and call for his immediate release," Hague said in a statement.

Libyan Prime Minister Ali Zeidan was freed Thursday after being held by gunmen for several hours, in the latest sign of the country's lawlessness since Moammar Gadhafi's 2011 overthrow.

The premier appeared in good health when he arrived at government headquarters after his ordeal at the hands of former rebel militiamen, waving to waiting well-wishers as he climbed out of an armored car.

An alleged top al-Qaida operative snatched in a U.S. commando raid in Libya was involved in plots that killed Americans and will be brought to justice, U.S. President Barack Obama said Tuesday.

Vowing that the United States will continue to hunt down regional terror groups, Obama told reporters that Abu Anas al-Libi "helped plan and execute plots that killed hundreds of people, a whole lot of Americans. We have strong evidence of that. And he will be brought to justice."

Libya's top political authority, the General National Congress, demanded on Tuesday that the United States hand back an alleged al-Qaida operative its forces seized from Tripoli in a weekend raid.

A GNC statement read out by spokesman Omar Hmidan stressed "the need for the immediate surrender" of Abu Anas al-Libi and described the U.S. operation as a "flagrant violation of (Libya's) national sovereignty."

Libya's Prime Minister Ali Zeidan insisted Tuesday that Libyan citizens must be tried in their own country, days after U.S. special forces captured a suspected al-Qaida leader in Tripoli.

Earlier, the Libyan government said it had summoned U..S ambassador Deborah Jones to seek clarification about the raid on Saturday, in which Abu Anas al-Libi was snatched from his car in broad daylight.

Libya's government summoned U.S. ambassador Deborah Jones to seek clarification over the capture by American special forces of an alleged al-Qaida operative in Tripoli, the foreign ministry announced on Tuesday.

Tripoli has said it was not informed in advance of the raid on Saturday, when Libi was snatched in broad daylight from his car in the capital.

Abu Anas al-Libi, captured in a daring U.S. raid, was once in Osama bin Laden's inner circle, but appears to have had few ties to Libya's new generation of jihadists.

Islamists inspired by al-Qaida's war on the West have flourished in chaotic post-Kadhafi Libya, but evince little interest in the core group founded by bin Laden in the 1990s, which has been decimated by arrests and U.S. drone strikes in the decade-long War on Terror.

Dozens of unarmed Libyan soldiers occupied the prime minister's office in Tripoli on Monday to demand unpaid wages, the privately-owned Alnabaa television reported.

The channel said the soldiers had been protesting against the "non-payment of their salaries for months."