The UN's peacekeeping chief on Tuesday called on South Sudan to withdraw its forces from the disputed Abyei region, warning their presence could further fuel tensions in the restive, oil-rich border area also claimed by Khartoum.

"We are deeply concerned about the presence of South Sudanese security forces in southern Abyei since October 2022," Jean-Pierre Lacroix told the Security Council, adding that additional military deployments took place in March and April of this year.

Warning their presence could "fuel tensions in a region already faced with deep political divisions," Lacroix said South Sudan should "withdraw all security personnel from the Abyei area as soon as possible."

The territory has been disputed since the south gained independence from Sudan in 2011, whereupon the disputed Abyei region was placed under UN protection.

Several thousand UN peacekeeping forces are deployed in the region and their work is being stymied by South Sudanese forces, Lacroix said.

The presence of the South Sudanese military has caused fear among the local population and repeatedly hindered the UN mission's movement, limiting its ability to protect civilians, Lacroix added.

Juba is also violating the 2011 agreement that left Abyei as a demilitarized zone, Lacroix said.

Violence is common in Abyei, with 54 people killed in one week alone earlier this year, including two UN peacekeepers.

Among the disputes have been ethnic clashes between the Abyei-based Ngok and their Twic rivals from the neighboring state of Warrap in South Sudan.