African Union mediator Thabo Mbeki arrived in Khartoum on Thursday to help push Sudan and South Sudan back to talks, which were suspended after border fighting last month.Sudan and South Sudan have not complied with a United Nations Security Council demand that they resume the talks by Wednesday, but Mbeki and other diplomats are nonetheless trying to get negotiations restarted.The former South African president will meet over two days with Sudan’s President Omar al-Bashir and other officials, foreign ministry spokesman Al-Obeid Meruh told AFP.He is also expected to visit the South Sudanese capital Juba as part of his diplomacy."He is encouraging both sides to put proposals on the table on the key issues that have divided the countries,” the US government’s top diplomat for Africa, Johnnie Carson, said on Wednesday."While there has not been a full resumption of discussions between the two sides, things are being done,” Carson, assistant secretary of state for African affairs, told Africa-based reporters in a telephone news conference."We want them to be done much faster, and with greater alacrity and commitment.”On May 2, the Security Council 2 gave Sudan and South Sudan two weeks to unconditionally resume negotiations. It threatened sanctions if its demands are ignored.The UN resolution called for a halt to the fighting and a resumption of talks to settle "critical” issues left unresolved after the South’s separation in July last year following a 1983-2005 civil war.These include oil payments, the status of each country’s citizens resident in the other, the status of the contested Abyei region, and resolution of disputed and "claimed” border areas as well as demarcation of the frontier.Mbeki arrived in Khartoum as the UN Security Council made a new demand that Sudan "immediately” withdraw all troops from Abyei, which it occupied one year ago.Withdrawal from Abyei was one of the demands under the May 2 Security Council resolution, but Sudan said it will pull out only after a joint administration for the territory has been set up.South Sudan, which withdrew its forces from Abyei as demanded, says Khartoum is blocking the creation of that administration.South Sudan’s government spokesman Barnaba Marial Benjamin told AFP on Thursday that the South’s delegation has been ready to talk but "Mbeki has not issued invites or given us a date” because Khartoum has been reluctant."I think they wanted to be sure that Sudan is coming” before inviting parties, he said, wondering why the AU has not criticised Sudan for "dragging its feet”.He said the AU "are changing the programme according to the whims of Khartoum. They must be open about this -- talks should have resumed.”Meruh, of Sudan’s foreign ministry, said earlier that Mbeki would discuss "details of negotiations, like the dates and the agenda,” during his visit.Susan Rice, the US ambassador to the UN, said it was no surprise that talks did not resume on Wednesday, but the aim is they take place without further delay.The international community would put "maximum pressure” on the two sides to secure new talks and an end to fighting, she said.Although violence has dropped significantly in recent days the two sides remain "locked and loaded” along their tense frontier, Rice added.