Former south rebel Sudan People's Liberation Army (SPLA) killed 22 army soldiers in the disputed area of Abyei, the Sudanese army said Friday, announcing the oil- producing area a "war zone."

Sawarmi Khalid Saad, spokesman of the Sudanese Armed Forces ( SAF), told a press conference that a SAF troop was ambushed Thursday by SPLA forces seven km north of Abyei town in the Abyei area located on the border between north and south Sudan, which was claimed by both sides.

Earlier Friday, the UN Mission in Sudan (UNMIS) had confirmed the attack, saying a SAF convoy escorted by UN peacekeepers had been targeted by unknown armed persons on their way to Goli, and two Sudanese soldiers were wounded in the fighting.