South Sudan's president heads to Sudan Saturday for talks on unresolved issues that could threaten security in the region.

President Salva Kiir's meeting with Sudan President Omar al-Bashir marks Mr. Kiir's first trip to Khartoum since his country won independence from Sudan in July.

The leaders are expected to address multiple issues facing the Abyei region, which borders both countries. The neighboring countries have yet to reach an agreement on the future of the oil rich region. A referendum on the issue was postponed earlier this year because they could not agree on who was eligible to vote.

On Tuesday, the U.N. secretary for peacekeeping operations said Sudan and South Sudan must redouble their efforts to withdraw troops from Abyei and allow displaced people to return peacefully.

South Sudan has withdrawn it troops from Abyei, but Sudan refuses to leave until all planned 4,200 Ethiopian peacekeepers have arrived. Currently, only half of the Ethiopian peacekeepers are in Abyei.

The presidents of South Sudan and Sudan are also expected to address the fighting in Sudan's Blue Nile and Southern Kordofan border area.

Forces partial to South Sudan have clashed with Sudanese troops.