Four members of the International Criminal Court were arrested and are being held in Libya, the tribunal said, calling on the authorities there to free them.

The ICC team had been held since Thursday, having travelled to Libya to meet Seif al-Islam, the detained son of slain leader Moammar Gadhafi, the statement said.

New fighting broke out in southern Libya on Saturday between members of the Toubou minority and government forces, the two sides said, with unconfirmed reports that at least five people were killed.

Tribal chief Issa Abdelmajid said the Toubou quarter of the town of Kufra came under shelling at 3:00 am (0100 GMT) by the Libya Shield Brigade, former rebels under government control sent to quell previous ethnic fighting.

The premises of the U.S. diplomatic mission in Libya's eastern city of Benghazi came under attack during the night but there were no casualties, embassy and security sources told Agence France Presse on Tuesday.

"There was an attack late last night on the United States office in Benghazi," a U.S. embassy official said, adding that one was hurt.

The first trial of a senior official accused of killing demonstrators in the 2011 uprising against Libyan leader Moammar Gadhafi opened on Tuesday.

Former foreign intelligence chief Bouzid Dorda is accused of ordering security forces to "kill demonstrators and fire live ammunition at them" during the 2011 uprising that ended Gadhafi’s rule.

A militia of Libyan ex-rebels entered Tripoli International airport with tanks and armored vehicles and completely blocked air traffic on Monday, a day after their leader was arrested, officials said.

"It is total confusion. Everyone is fleeing. Several armored vehicles and tanks are positioned on the tarmac, blocking traffic," an official at the airport told Agence France Presse.

A military court handed stiff prison terms to 19 Ukrainians, three nationals from Belarus and two Russians accused of serving as mercenaries for ousted leader Moammar Gadhafi in Libya's conflict last year.

One of the Russians, judged to have been the coordinator, was condemned to life imprisonment while the others were sentenced to 10 years' hard labor.

Seif al-Islam, the son of Libya's slain strongman Moammar Gadhafi, has not been transferred to Tripoli because the ex-rebels holding him have not been paid, Libya's envoy to the International Criminal Court said on Monday.

"The failure of the National Transitional Council to fulfill its promise to pay the salaries of the thuwar (revolutionaries) of Zintan for six months' work, for an amount of not more than 1.7 million dinars ($1.36 million), led them to cancel Seif al-Islam's transfer to prison in Tripoli," Ahmed al-Jehani told Agence France Presse.

Residents in the eastern city of Benghazi, cradle of the revolt that led to the ouster and death of Libyan leader Moammar Gadhafi, headed to the polls Saturday to elect a local council.

"This is a first step in the transition from revolution to state building," Suleiman Zubi, head of the local electoral committee, told Agence France Presse.

Russia cautioned Western powers on Thursday against launching "hasty" wars that could lead to the rise of radical Islamist factions and even result in regional nuclear wars.

Prime Minister Dmitry Medvedev told a legal forum ahead of his visit to the G8 summit as Russia's official representative at Camp David that Moscow noted numerous examples of powers infringing on the sovereignty of other states.

Seven people were killed and more than 20 wounded as gunmen raided the oasis town of Ghadames on the border with Algeria on Wednesday, Libya's government spokesman said.

"There were clashes in the city of Ghadames," Nasser al-Manaa said.