UNITED NATIONS, Feb. 18 (Xinhua) -- UN officials warned on Wednesday over deadly drone attacks by both sides in the Sudan civil war while a humanitarian convoy reached two cities under siege.

"We join our high commissioner for human rights, Volker Turk, in expressing alarm at reports that more than 50 civilians were killed in drone strikes carried out by parties to the conflict in Sudan over two days this week," said Stephane Dujarric, spokesperson for the UN secretary-general.

"These latest killings are yet another reminder of the devastating toll on civilians from the escalating use of drone warfare in Sudan," Dujarric said. "We renew our call on both sides to cease the violence and engage in dialogue toward a ceasefire."

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said Wednesday that a 26-truck convoy with life-saving supplies for more than 130,000 people reached the cities of Dilling and Kadugli in South Kordofan, the first to arrive in more than three months.

The convoy, led by the World Food Programme, the UN Children's Fund and the UN Development Programme, was delayed for several weeks due to high levels of insecurity along the route, it said.

OCHA said Dilling and Kadugli were recently under prolonged sieges, with commercial and humanitarian supply routes cut off, contributing to spiraling humanitarian needs. Recent analysis from the Integrated Food Security Phase Classification committee pointed towards likely famine conditions in both cities.

"It is now critical to build on this break-through with sustained access to people in need across South Kordofan and the broader Kordofan region," the office said. "This requires the facilitation of the parties to the conflict in line with their obligations under international humanitarian law."

OCHA called on donors to step up their support, noting that "this year's humanitarian response plan calls for 2.9 billion U.S. dollars to reach more than 20 million people -- two out of every five people -- across the country." ■