THE UNITED NATIONS, United States: The UN on Tuesday condemned an attack the day before on a “clearly marked” humanitarian convoy in South Sudan that killed five humanitarian workers working with the United Nations.

“We are deeply saddened by the killing of five humanitarian workers, whose convoy, operated by a local partner, was ambushed yesterday in Duk County in Jonglei State,” UN spokesman Stephane Dujarric said.

He said four other humanitarian workers were injured in the attack “and several civilians were reportedly killed or injured.”

“Our colleagues tell us that their convoy was clearly marked as a humanitarian convoy,” he said.

Attacks on humanitarian workers — which are becoming more frequent — “are unacceptable and violate international humanitarian law,” Dujarric said, calling for a prompt investigation.