BENGHAZI, Libya - The United Nations says the situation in a remote southern part of Libya where more than 100 people were killed in tribal warfare this month remains tense although a cease-fire brokered by local officials is still holding.

Monday's statement by the UN Support Mission in Libya said that as much as half of the population of Kufra has fled and that around 200 foreign migrants are still waiting to be moved out of the area.

The clashes that broke out Feb. 11 underscore the struggle facing Libya's new leaders to enforce security, disarm people and unify multiple militias that took part in an eight-month civil war that ended with the capture and killing of longtime ruler Moammar Gadhafi in October.

Dozens were killed this month by rockets, mortars and gunfire that rocked residential areas in the desert town, which is some 800 kilometres away from the more populated coastal city of Derna.

The UN said it provided people there with food, medicine, mattresses, blankets and hygiene kits to vulnerable communities whose basic services have been interrupted by fighting.

The injured packed the city's three-room hospital for days during the clashes. Many had no beds to sleep on. There was one doctor and 15 nurses using empty bottles of water as blood bags. Patients had to share one ventilator.

For days, rescuers were unable to get to the bodies of victims who were left on the street.

An Associated Press reporter who was in Kufra during the clashes saw at least 160 houses demolished by rockets in one neighbourhood. Families gathered inside a school seeking shelter, but even that came under shelling.

Shops were closed for days, and no one could walk in the street. If one tribe took over one square, the other tribe opened fire and drove it out.

During that time the powerful Arab tribe of al-Zwia clashed with the African Tabu tribe near Kufra, a border area where Libya, Chad and Sudan meet. The region is a hub for the smuggling of African migrants, goods and drugs.

The two groups are old rivals and speak different languages. The Tabu have long complained of discrimination under Gadhafi.

Abdel-Majed, once an opposition leader who founded a group calling for an autonomous state for the Tabu people, said Gadhafi's regime would expel Tabu students from schools, take their passports and deprive families of bank loans.

Gadhafi also tried to change the demography of the city by offering incentives to al-Zwia tribe members to move to Kufra in order to outnumber the Tabu.

The clashes, erupted after an al-Zwia smuggler shot and killed six Tabu tribesmen guarding a border crossing, lifting the lid on a long suppressed ethnic conflict.

In another sign that the government is struggling to reign in the country's numerous armed factions, the U.S.-based Human Rights Watch called on a Mistrata-based militia Monday to immediately release two British journalists and three Libyans travelling with them.

The rights group said that the Saraya Swehli militia detained the British citizens nearly a week ago. They work as freelance journalists for Iran's Press TV.

The Middle East director at Human Rights Watch, Sarah Leah Whitson, said in a statement that militias must stop detaining people and called on the Libyan government to take charge of militia detention facilities. The rights group says the militia has denied them access to the journalists.