A Sudanese military plane has crashed in a rural area west of the capital Khartoum, killing at least 13 of the 20 armed forces personnel on board and injuring others.

The plane was traveling from Khartoum to El Fasher in the country's strife-torn Darfur region, army spokesman Al-Sawarmi Khalid.

He did not say what was thought to have caused the crash.

"Some were killed and some were injured," he said, adding that the Antonov 12 transport plane was also carrying military equipment.

There have been several crashes in Sudan in recent years, where years of US sanctions have made it difficult for airlines to get spare parts for their fleets.

In August, 32 people including a government minister died when a plane taking them to an Islamic festival in a southern border state crashed. State media blamed that accident on bad weather.

Government forces have been battling an insurgency in Darfur since rebels took up arms in 2003, accusing the central government of neglecting the remote region.