BENGHAZI, Libya -- The United Nations envoy to Libya said Tuesday that it would be impossible to hold next week's planned peace conference amid ongoing fighting between rival militias for control of the capital, Tripoli.
Ghassan Salame promised to "work day and night" to de-escalate the violence. He said in a statement that the U.N. intends to convene the conference as soon as conditions permit, but that it would be impossible to hold the talks "to the backdrop of artillery shelling and air raids."
The U.N. has been unable to halt the advance on Tripoli by Khalifa Hifter, a military commander based in the country's east. The push began last week and has killed 51 people, including both combatants and civilians. The capital is controlled by militias based in the country's west, which support the U.N.-backed government based there.
Salame said the days of deadly clashes had squandered a "historic opportunity" for Libyans. A national conference set for mid-April was to pave the way for elections and the unification of the country's ruling administrations.
Fighting for the capital has instead threatened to plunge the North African nation deeper into chaos and ignite civil war on the scale of the 2011 NATO-supported uprising, which devolved into a ruinous conflict that killed longtime dictator Moammar Gadhafi.
In a video filmed by A24 News Agency, young men in mismatched garb fired machine guns and RPGs while forcing the retreat of armored vehicles — allegedly part of Hifter's forces — in a town called Ain Zara, around 15 kilometers (9 miles) southeast of Tripoli.
On Monday, Tripoli's only functioning airport was closed after being hit by an airstrike, which Hifter's forces acknowledged having launched. The Mitiga airport is barely 8 kilometers (5 miles) east of the city center.
The U.N. said the recent fighting has displaced some 3,400 people and blocked emergency services from reaching casualties and civilians.
In New York, U.N. High Commissioner for Refugees Filippo Grandi warned that combat in Tripoli was also taking a toll on refugees and migrants held in detention centers. He said U.N. workers "braving the bullets, literally, have evacuated 150 refugees from a detention center" and moved them to another center in the capital.
Speaking to the Security Council and journalists on Tuesday, Grandi said both Libyans and refugees were at risk of becoming displaced if the fighting continues. Many Libyans fled west to neighboring Tunisia during the 2011 war.
In a sign that the Islamic State could also be making a comeback elsewhere in Libya, an attack overnight in a small town in central Libya killed at least three people, including the mayor. IS claimed responsibility for the attack, which took place in the town of al-Fuqaha, south of the coastal city of Sirte, a former IS bastion.
A resident of the town, Rabie al-Zidani, said the mayor and two other security officials were beheaded, and a lawmaker, Ismail al-Sharif, confirmed the three deaths and said militants had torched several houses.
IS, which had previously attacked the town in October, said in an online statement that the strike comes in "revenge for the blessed Levant Waliya." This was an apparent reference to the defeat of IS in its final stronghold in Syria last month by the United States' local allies, the Kurdish-led Syrian Democratic Forces.
The jihadist group said militants stormed the houses of the "apostates" in reference to local municipal and security officials, killed them, burnt their homes and briefly seized control of the town before withdrawing after taking captives.
After ruling Sirte for nearly a year, IS was defeated in Libya in 2016 by a U.S.-backed operation.
Associated Press writer Edith M. Lederer at the United Nations contributed to this report.