The United Nations says a grenade strike in Sudan's Darfur region has killed one aid worker and critically wounded at least two other workers.
Authorities in Nyala, South Darfur's largest city, say the aid workers were caught in the crossfire of a gunfight Thursday between competing security forces.
A U.N. statement says a rocket-propelled grenade hit the office of an international organization. The U.N. did not name the organization.
The statement also said there were reports some offices and premises of international organizations in Nyala were looted.
Officials in South Darfur have declared a curfew in Nyala.
Darfur has been racked by fighting and violence since rebel groups launched an uprising against Sudan's central government in 2003.
The U.N. estimates more than 300,000 people have died and close to two million civilians have been forced from their homes. Periodic fighting and tribal clashes continue.
An earlier version of this story misspelled Nyala.