KHARTOUM, March 11 (Reuters) - Sudan's army said on Monday it fought off a rebel advance in a volatile state bordering South Sudan, but the insurgents said they had made a "tactical withdrawal" after a successful operation.

The remote border area has been plagued by conflict since South Sudan broke away from Sudan as an independent country in July, 2011.

 

Fighting between Sudanese government forces and rebels, who sided with the south in a decades-long civil war that led up to the secession, has forced hundreds of thousands of people to flee their homes.

Sudan's armed forces spokesman Al-Sawarmi Khalid Saad said the army had repulsed an insurgent attack on the Surkum area in Blue Nile state.

"The armed forces managed to ... inflict heavy losses on the rebels," in fighting had lasted from late Sunday until Monday morning, he told Reuters.

Arnu Lodi, a spokesman for the rebel Sudan People's Liberation Movement North (SPLM-N), gave a different account.

"We withdrew for tactical reasons," he said, adding that the pull-out followed rebel attacks on government camps in the area on Sunday.

The rebels accuse the Khartoum government of discriminating against their communities on the border, and have joined an alliance with insurgents from other areas, vowing to topple Sudan's President Omar Hassan al-Bashir

The two sides often give conflicting accounts of the fighting in the remote regions, which are extremely difficult to verify independently because of government restrictions on access for independent observers.

The violence in Blue Nile state and another border state, South Kordofan, has strained relations between the two countries.

Khartoum accuses South Sudan of supporting the rebels, which Juba denies.

South Sudan ordered its troops out of a buffer zone on the roughly 2,000-km border on Monday as agreed at African Union-brokered talks, but diplomats remain cautious and say they are waiting for concrete signs of movement.