(AFP) - A regional United Nations envoy expressed concern Monday that fighting between the forces of two generals vying for power in Sudan is drawing closer to the country's border with South Sudan and the disputed Abyei region.

The conflict that erupted in April between troops loyal to Sudanese army chief Abdel Fattah al-Burhan and the Rapid Support Forces of General Mohamed Hamdan Daglo has "significant humanitarian, security, economic and political consequences that are a matter of deep concern for the South Sudanese political leadership," said UN special envoy for the Horn of Africa, Hanna Tetteh.

With its military offensive in West Kordofan and seizure of Belila's airport and oil field, "the RSF is getting closer to Abyei, controlling parts of the border with South Sudan," Tetteh said during a UN Security Council meeting.

The military confrontation between the two rival groups, she said, therefore "is getting closer to the boundary with Abyei and the border with South Sudan."

Tetteh also noted that, given the proximity of certain elements of the Arab Misseriya tribe to the RSF and recruitment campaigns by the warring parties, these military operations could upend Abyei's social fabric and the fragile coexistence between the Misseriya and the Ngok Dinka tribe.

The oil-rich region has long experienced tensions between Ngok Dinka communities and semi-nomadic Misseriya herders, who cross the lands searching for pasture.

Located between Sudan and South Sudan, Abyei has been a flashpoint since the South gained independence in 2011.

The war between Burhan and his ex-deputy Daglo has left more than 9,000 dead since April, according to a UN report.

The Security Council is to decide this month whether to extend the 12-year-old UN peacekeeping mission in Abyei which currently comprises some 4,000 military and police personnel.

© Agence France-Presse