Sudan says it is cutting off talks with South Sudan, as the sides clash in a disputed border region.

State radio Wednesday quoted Vice President Al-Haj Adam Yusuf as saying there will be no talks with the south and that Sudan must protect its border.

Sudan is accusing South Sudan of launching attacks in the oil-rich Heglig area with the help of rebels who have been fighting Khartoum since June of last year.

Sudan's deputy foreign minister, Ramatallah Mohammed Osman, tells VOA that Khartoum wants the south to remove its troops.

“But now we ask the international community to exert pressure on the government of South Sudan to withdraw its forces immediately from this part of Sudan.”

The south says it pursued Sudanese troops into Heglig after repulsing an attack Tuesday. South Sudan's military says it has taken control of the town.

The African Union issued a statement Wednesday urging both sides to respect each other's territorial integrity. It also called on the south to remove its troops from Heglig.

The AU has tried to mediate several deep and bitter disputes between Sudan and South Sudan but has made little progress.

Key issues include borders, the sharing of oil revenue and the status of nationals in each other's territory.

Both countries have suggested the possibility of renewed war. South Sudan separated from Sudan last July, six years after the two-decade Sudanese civil war.

The AU's Peace and Security Panel says that in the wake of the fighting, Sudan has ruled out any possibility of a summit between its president, Omar al-Bashir, and South Sudan President Salva Kiir.

The two men were scheduled to meet last week but the summit was cancelled because of an earlier round of fighting over Heglig.

The United Nations Security Council is scheduled to hold a closed-door session on Sudan Wednesday. That meeting was called to discuss the situation in Abyei, another contested region.