A Sudanese government official says hundreds of rebels have been killed in clashes with army troops in Southern Kordofan state.

The governor of Southern Kordofan, Ahmed Haroun, told reporters the violence erupted on Monday, after insurgents attacked the city of Teludi. Khartoum says its army repelled the assault.

Haroun said the rebels were backed by newly-independent South Sudan.

Sudan has repeatedly claimed that South Sudan's military is supporting rebels in Southern Kordofan, an oil-rich state on the border between the countries. South Sudan has denied the claim.

Violence has grown worse along the border since July, when South Sudan formally declared independence from Sudan.

Sudanese forces have been battling Southern Kordofan's ethnic Nuba rebels, who they view as supporters of South Sudan. The Nuba fighters sided with the south during Sudan's 21-year, north-south civil war.

The United Nations has said there is strong evidence that Sudanese forces have committed atrocities in the border area, including mass killings, arbitrary detentions, kidnappings, attacks on churches.