The rival Sudans agreed in June, one month after Khartoum forces overran most of Abyei, to pull their troops out. But neither has kept the accord, according to UN officials. Border tensions have mounted as disputes have spread to other regions, particularly on the Sudanese side of the frontier. The 15-member Security Council demanded the withdrawal in a resolution which extended the mandate of the UN Interim Security Force for Abyei, UNISFA, for five months. The council "demands that the governments of Sudan and South Sudan redeploy all remaining police and military personnel from the Abyei area immediately," said the resolution. The council said it was "deeply concerned by the reported buildup of armed forces of Sudan and South Sudan near their mutual border and inflammatory rhetoric from both sides, which increases the risk of direct confrontation." Sudan and South Sudan formally separated in July but have been involved in a series of clashes since. More than 100,000 people fled to the south when Khartoum forces entered Abyei in May. Last week the Security Council extended UNISFA's mandate to include monitoring the border around Abyei.