Updated

The death toll from fighting between rival armed groups in Libya's capital Tripoli has climbed to at least 50 people including civilians, authorities said Tuesday, as the U.N. mission stepped up efforts to broker a cease-fire.

Fighting erupted last week when the Seventh Brigade, militias which hail from Tarhouna, a town about 40 miles (60 kilometers) south of Tripoli, attacked southern neighborhoods of the capital. The Tripoli Revolutionaries' Brigades and the Nawasi Brigade — militias which support the Tripoli-based U.N.-backed government — have come to the city's defense.

At least 138 people, including civilians, have since been wounded, the Health Ministry said in a statement.

Libya slid into chaos after the 2011 uprising that overthrew ruler Moammar Gadhafi and led to his death. The country is currently governed by rival authorities in Tripoli and the country's east, each of which are backed by an array of militias. Other armed groups have carved out fiefdoms across the country, with many profiting from smuggling and extortion.

The U.N.'s Office of the High Commissioner for Human Rights in Geneva has voiced concern about the impact of the fighting on migrants and internally displaced people. Spokeswoman Liz Throssell said Tuesday that some of the nearly 8,000 arbitrarily detained migrants are trapped in detention centers in areas where fighting has taken place, without access to food or medical treatment.

She said at least 21 civilians have been killed, including two women and two children since Aug. 26.

Also on Tuesday, the U.N. Refugee Agency called on parties to the fighting to "spare civilians and civilian infrastructure and allow safe passage for those seeking refuge in safer areas."

The clashes have forced the U.N.-backed government to declare a state of emergency in and around Tripoli, saying the fighting is "an attempt to derail peaceful political transition" in the country. The government said it "could not remain silent over the attacks on Tripoli and its suburbs, which is a violation of security in the capital and of citizens' safety."

Mohamed Buisier, a political analyst, said the fighting was expected as the armed groups protecting the government in Tripoli were getting "larger portions of financial incentives."

"This is a normal thing after years of failure. ... We are in a new phase where nobody can strip the militias from their arms. Libya needs an international peace-keeping force," he said.

The U.N. mission in Libya has been preparing for a meeting between the warring parties in an effort to put an end to the fighting. It called on "the various concerned parties" to meet on Tuesday for an "urgent dialogue on the security situation" in Tripoli.

______________

Magdy reported from Cairo.