Former rebel gunmen freed Libya's prime minister on Thursday after holding him for several hours in reprisal for the capture by US forces at the weekend of a Libyan al Qaeda suspect in Tripoli, officials said.
A Reuters journalist at the scene said protesters had opened fire at the building where Ali Zeidan was being held to demand that the group, which is affiliated with the government, free the premier.
"The prime minister has been released," a government official said.
A security source also said Zeidan was free.
Two years after a revolution ended Muammar Gaddafi's 42-year rule, Libya is in turmoil, with its vulnerable central government and nascent armed forces struggling to contain rival tribal militias and Islamist militants who control parts of the country.
The militia, which had been hired by the government to provide security in Tripoli, said it "arrested" Zeidan after US Secretary of State John Kerry said Libya had a role in the weekend capture in the city of Abu Anas al-Liby.
"His arrest comes after ... (Kerry) said the Libyan government was aware of the operation," a spokesman for the group, known as the Operations Room of Libya's Revolutionaries, told Reuters. Before his release, an official in the Interior Ministry anti-crime department told the state news agency that Zeidan, a former diplomat and exile opposition activist against Gaddafi, was being held there and was being treated well.
The Libyan government in a statement confirmed the premier was taken at dawn to "an unknown place for unknown reasons." The prime minister was taken from the Corinthia Hotel, where many diplomats and top government officials live.
It is regarded as one of the most secure places in Tripoli. The kidnapping, however brief, raised the stakes in the unruly OPEC nation, where the regional factions are also seeking control over its oil wealth, which provides Libya with the vast bulk of government revenues. Brent oil prices rose on the news.
"Everybody is watching this... We still haven't seen any disruption to supply from Libya, so we don't expect a spike in prices," said Ken Hasegawa, a commodity sales manager at Newedge Japan.
A mix of striking workers, militias and political activists have blocked Libya's oilfields and ports for more than two months, according to Oil Minister Abdelbari Arusi, resulting in over $5 billion of lost revenues. He said on October 2 that oil exports could return to full capacity in days once the strikes ended.