The split decision regarding the oil-rich region of Abyei was seen as a boost to the 2005 U.S.-brokered peace treaty between the Khartoum-based regime and former southern rebels in the Sudan People's Liberation Movement, or SPLM. Despite reaching a cease-fire and agreeing to form a power-sharing government, northern and southern troops fought briefly last year as a result of unresolved questions about who would control Abyei along the north-south border. Many worried the dispute could reignite Sudan's 21-year civil war. Officials in Khartoum characterized the panel's decision Wednesday as a victory. The government had rejected a previous panel's ruling that the oil fields lay in the disputed area. Both sides agreed last year to have the matter settled by the Permanent Court of Arbitration in The Hague. SPLM officials expressed disappointment but vowed to uphold the ruling. 'The court didn't give (us) all our rights, but we respect it,' said Arop Mayok, the SPLM's chief administrator in Abyei. Under the decision, the lucrative Heglig oil fields, partly owned by the Sudanese government, will stay part of the north. Most of Sudan's other known oil reserves are in the south. Analysts said the decision probably would appease northerners, who had been worried that they might be left without oil in the event that southerners, including those in Abyei, vote for independence in a 2011 referendum. Southerners won control of key tribal lands and will be able to begin resolving a demarcation battle that has been a key obstacle to implementing the 2005 treaty. Analysts warned that the key test of the ruling would take place as the two sides moved to enforce the decision. Troops from both sides have been stationed in and around the area, as are United Nations peacekeepers. Already some northern-leaning tribes, which might be displaced by the ruling, are threatening to reject the decision. Mohamed Omer Alansari, a Messieriya tribal chief allied with the north, accused the government of abandoning his community and not doing enough to protect his tribe's lands, which he said would now be part of the Abyei region. 'The government only wanted the oil,' he said. 'They didn't really care about the benefit of the people.' Special correspondent Alsanosi Ahmed in Khartoum contributed to this report. 