A Sudanese helicopter gunship crashed at an air base in North Kordofan state on Friday, official media said, but there was no immediate confirmation of casualties or what caused the incident.

The aircraft went down at the airport in El Obeid, the state capital, SUNA news agency said.

"Now we are working to get more information about casualties," SUNA quoted army spokesman Sawarmi Khaled Saad as saying.

El Obeid is a base for the Sudanese military but there is no known rebel activity in that immediate area.

Sudan's armed forces since June have been battling rebels further south in adjacent South Kordofan state.