UNITED NATIONS, Jan. 22 (Xinhua) -- UN humanitarians said Thursday that they are deeply alarmed by the growing impact of drone attacks in Sudan's North Kordofan state, which are endangering civilians and further choking aid access.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said that multiple drone strikes were reported on Tuesday in the villages of Rehaid Al Nuba, Al-Shaatout and Um Andaraba, about 100 km southeast of El Obeid, along a critical logistics corridor, threatening eastern supply lines to the capital.

The village of Wadi Al-Hout, about 30 km north of El Obeid, was also reported to have been hit on the same day, highlighting the increasing frequency and geographic spread of the aerial attacks across North Kordofan.

There was no word on who carried out the aerial raids.

Continued insecurity is placing civilians at heightened risk and further restricting the movement of humanitarian supplies. All parties must protect civilians and civilian infrastructure, and ensure rapid, safe, unhindered and sustained humanitarian access, said OCHA.

In North Darfur state, the United Nations and humanitarian partners reported severe shortfalls in food assistance for newly arrived, displaced families in Daba Naira camp, highlighting the need to scale up food distribution urgently, said the office.

The World Food Programme reported that despite severe access and funding constraints, it reached 3.6 million people last month, including 1.7 million in Darfur. However, it warned that by the end of March, it will have exhausted its food stocks in Sudan and requires 700 million U.S. dollars to sustain life-saving operations through June.

OCHA said the crisis is also deepening for children as Save the Children reported that more than 8 million children across Sudan have been out of classrooms for about 500 days.

OCHA said that in North Darfur, only 3 percent of more than 1,100 schools remain open, while schools in West Kordofan, South Darfur and West Darfur states are operating at just 15 percent to 27 percent capacity, citing data from aid partners.

"Months of unpaid salaries have eroded teacher morale, forcing some to abandon their posts," OCHA said. "Without urgent funding to pay teachers, rehabilitate learning spaces and provide essential supplies, Sudan's education system risks collapse."

OCHA urged donors to step up support, adding that the United Nations and its partners are calling for 2.9 billion dollars to reach more than 20 million people who need assistance. ■