UNITED NATIONS, July 21 (Xinhua) -- Security concerns halt the delivery of relief supplies and staff into Ethiopia's Tigray region as aid operation restrictions within the area ease, UN humanitarians said on Wednesday.

While there are improvements in access within Tigray, the last entry point open to Tigray -- the road from the neighboring Afar region by way of Semera city -- remains blocked due to security reasons, preventing movement of humanitarian personnel, food stock, fuel and other humanitarian goods from entering the region, said the UN Office for the Coordination of Humanitarian Affairs (OCHA).

Humanitarian stocks are rapidly depleting inside Tigray. As of Monday, the World Food Programme (WFP) and partners will only have enough food stock to feed about 1.9 million people with common food baskets for one round.

"Shortages of fuel and cash, as well as a communications blackout, are significantly hindering the resumption and preventing the scale-up of humanitarian response," OCHA said. "Nongovernmental organizations and UN agencies are running out of cash and are unable to pay staff or suppliers."

Unless fuel, cash, supplies and aid workers are able to enter Tigray in the coming days, some humanitarian programs will not be able to continue, the office warned.

The UN Humanitarian Air Service's first regular flight is scheduled to begin on Thursday.

The United Nations continues to call for the restoration of electricity, communications, commercial flights and the banking system to prevent further deterioration of the humanitarian situation.