UNITED NATIONS, June 3 (Xinhua) -- A UN spokesman on Tuesday condemned an attack that killed five UN aid convoy workers in Sudan.

"We condemn in the strongest terms this horrendous act of violence against humanitarian personnel who literally put their lives at risk attempting to reach vulnerable children and families in the famine-impacted areas," said Stephane Dujarric, chief spokesman for UN Secretary-General Antonio Guterres.

Dujarric said several others were injured in the attack Monday night on a convoy of more than 30 vehicles, including 15 World Food Programme (WFP)-UNICEF trucks carrying food and nutrition supplies.

The spokesman said they were parked on the side of the road waiting for clearances at the end of the journey from Port Sudan in the country's northeast to El Fasher in the southwest. They were just 80 km from El Fasher, the embattled North Darfur State capital.

"The agencies were negotiating access to complete the journey to El Fasher when it was attacked," he said. "The route was shared in advance, and parties on the ground were notified and aware of the location of the trucks. Multiple trucks were burned in the attack, and critical humanitarian supplies were damaged. It is devastating the supplies have not reached the civilians in need."

The spokesman said it was the first UN humanitarian convoy that was going to make it to El Fasher in over a year. It was believed the aerial attack was carried out by drones.

"We call for safe, secure operating conditions and for international humanitarian law to be respected by all parties, not just in Sudan, but in all conflict-impacted countries," Dujarric said. "Under international humanitarian law, aid convoys must be protected, and parties have the obligation to allow and facilitate rapid and unimpeded passage of humanitarian relief for civilians in need." ■