Former South African President Thabo Mbeki was in Khartoum on Friday to try and push Sudan and South Sudan back to the negotiation table.

Acting as mediator for the African Union, Mbeki is encouraging both sides to put proposals on the table on the key issues that have divided the countries, Johnnie Carson, U.S. assistant secretary of state for African affairs, told AFP earlier this week.

Sudan and South Sudan have been teetering on the brink of war since the south sent troops into the disputed Heglig oilfields, which lies on the border between the two nations. South Sudan has since withdrawn from the town, but ongoing negotiations about an oil revenue-sharing program, which is seen as a necessity for stability in the region, have been halted indefinitely.

Neither side has yet complied with a United Nations Security Council resolution that called for peace talks to begin by May 16. The resolution called for Sudan to withdraw its troops from the Abyei region, which has been occupied since last year, and the Security Council has threatened to impose sanctions if its demands are ignored.

While there has not been a full resumption of discussions between the two sides, things are being done, said Carson, We want them to be done much faster, and with greater alacrity and commitment.

According to the Sudan Vision Daily, Sudan's President Omar al-Bashir is trying to steer the talks toward security issues, again claiming that the south is supporting antigovernment rebels in the South Kordofan and Blue Nile states. South Sudan has said that Bashir's claims were an attempt to stall talks, and Juba has blamed the north for the continued bombings of South Sudanese border towns.

Sudan has denied the allegations, saying there is no proof of the south's claims.