UNITED NATIONS, May 7 (Xinhua) -- Drone strikes in the aid hub of Port Sudan are choking the delivery of relief and the movement of personnel to facilitate distribution, a UN spokesperson said on Wednesday.

Stephanie Tremblay, an associate spokesperson for UN Secretary-General Antonio Guterres, said the Red Sea port is a key entry point for aid and humanitarian personnel in Sudan, and the attacks thwarted the movement of both.

She said the World Food Programme suspended its UN Humanitarian Air Service operations on Sunday and won't resume them until conditions are safe, further straining the delivery of urgently needed assistance.

The northeast Sudan port was not the only target of drone raids.

She said the UN Office for the Coordination of Humanitarian Affairs (OCHA) reports that drone attacks affected the states of Kassala, east of Khartoum, and River Nile state, north of the capital. Earlier this week in Kassala, strikes near the airport displaced about 2,900 people and led to the temporary suspension or relocation of some aid activities.

"River Nile state is still facing a power blackout following a drone strike on the transformer station in Atbara on April 25," Tremblay said. "The outage is contributing to growing fuel and bread shortages and long queues at petrol stations and bakeries."

Under-Secretary-General for Humanitarian Affairs Tom Fletcher expressed deep concern over the Port Sudan drone strikes, saying that international humanitarian law must be respected and that constant care must be taken to spare civilians and civilian infrastructure.

Drone attacks on Tuesday struck strategic sites in Port Sudan, including an international airport, a hotel near the temporary presidential palace, and an oil export port, according to eyewitnesses.

Although no group officially claimed responsibility, the Sudanese military has blamed the paramilitary Rapid Support Forces for the drone attacks, which started on Sunday.

The port city has been serving as a temporary capital in the wake of devastating attacks on the traditional capital of Khartoum. ■