The U.N. humanitarian coordinator in Libya says 2,800 people have been displaced by fighting between rival militias over the capital, Tripoli.

Maria do Valle Ribeiro said Monday that clashes have prevented emergency services from reaching casualties and civilians, and have damaged electricity lines.

She warned that the increased violence is worsening the situation for migrants held in Tripoli's detention centers.

Fighting was underway Monday at the international airport, some 24 kilometers (15 miles) from central Tripoli.

The self-styled Libyan National Army, led by Khalifa Hifter, began an offensive against the capital last week.

Rival militias that support the U.N.-backed government in Tripoli have vowed to recapture all the areas recently seized by Hifter's forces.

The two sides reported that at least 41 people, including civilians, had been killed since Thursday.