A grenade strike in Sudan’s Darfur has killed one aid worker and critically wounded two others as violence worsens in the region

A grenade strike in Sudan's Darfur has killed one aid worker and critically wounded two others as violence worsens in the region, the United Nations said.
  
Officials in South Darfur state declared a curfew and blamed Thursday's fighting in the region's largest city Nyala on "differences" between members of the security forces.
  
The previous day in Darfur, assailants fired on an ambulance and wounded three UN peacekeepers during an ambush, the UN's peacekeeping chief said. The latest incidents add to the worsening security situation in Sudan's far west.
  
The UN's humanitarian agency OCHA said in a statement that a Sudanese staff member working for an international NGO was killed and three others injured "as a result of a rocket-propelled grenade hitting an NGO office".
  
"Of the three injured aid workers, two are reportedly in a critical condition and are currently receiving treatment in Nyala hospital." OCHA said it appeared the NGO office, which it did not name, became caught in the crossfire when fighting erupted in the city at about midday.
  
"There are also reports that some offices and premises of international organizations in Nyala were looted", it said.
  
The incident occurred during a resumption of fighting in the centre of the city after the killing overnight of a notorious local bandit who was also a paramilitary officer.

The violence came as United Nations peacekeeping chief Herve Ladsous visited Darfur. He called the attack by an armed group against the African Union-UN Mission in Darfur (UNAMID) "totally unacceptable".

Ladsous, the UN's Undersecretary General for Peacekeeping, told reporters that "what is even worse is that an ambulance which was with the convoy, an ambulance showing very clearly the red crescent, was shot at. And I could myself touch the holes of the bullets in the ambulance."