Eastern forces and troops loyal to the government in Tripoli fought on the outskirts of Libya's capital Wednesday as the humanitarian crisis escalates in the war-torn country with nearly half a million children at immediate risk, UNICEF revealed.

In a statement Tuesday, the U.N.'s children agency underscored that nearly 500,000 children in Tripoli and tens of thousands more in and around the Libyan capital of Tripoli are "at direct risk" due to the escalating violence. UNICEF called on all parties "to protect every child at all times and keep them out of harm's way in line with International Humanitarian Law," while urging both sides "to refrain from committing grave violations against children, including the recruitment and use of children in fighting."

The Libyan National Army (LNA) forces of eastern commander Gen. Khalifa Haftar had taken up positions in the suburbs about 11 kilometers south of the center, with steel containers and pickup trucks mounted with machine-guns blocking their way into the city. Residents reported LNA planes buzzing around overhead in Tripoli and the sound of clashes on the outskirts of the city. Haftar's forces briefly took the former international airport earlier in the week, but the head of Libya's U.N.-backed government Fayez Serraj's fighters won that back; however, the LNA remained entrenched further south, witnesses said.

The U.N. said that at least 4,500 Tripoli residents had been displaced, most moving away from conflict areas to safer districts of the city. But, many civilians were trapped and cut off from emergency services.

As well as the humanitarian consequences, renewed conflict in Libya threatens scupper the U.N. peace plan and encourages militants to exploit the chaos. The U.N. envoy to Libya Ghassan Salame said Tuesday that it would be impossible to hold next week's planned peace conference amid ongoing fighting between rival militias seeking control of the capital, Tripoli. Salame 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 against "the backdrop of artillery shelling and air raids." Salame said that 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 two different ruling administrations.

Libya has remained dogged by turmoil since 2011 when a NATO-backed uprising led to the ouster and death of former President Moammar Gadhafi after more than four decades in power. Since then, Libya's stark political divisions have yielded two rival seats of power, one in Tobruk and another in Tripoli and a host of heavily armed militia groups. The military push by Haftar's LNA, allied with a parallel eastern administration based in Benghazi, marked a dangerous escalation of a power struggle that has dragged on since the overthrow of former leader Gadhafi. Haftar is not recognized by the international community, as the elected parliament of the country is centered in Tripoli. However, Haftar, with financial and political support from certain countries, including some Gulf states, has appeared as an influential actor in the war-torn country.