The UN Security Council is concerned that the fighting in Abyei between northern and southern Sudanese forces is threatening the landmark peace deal between the two sides, said Britain's UN ambassador Tuesday. John Sawers and several other members of the UN Security Council flew to southern Sudan after visiting Djibouti to encourage peace talks in Somalia. The delegation is looking to shore up the Comprehensive Peace Agreement that ended more than two decades of civil war between northern and southern Sudan. It's "too early" to talk about it as a crisis. "But we will certainly be wanting to talk to President Salva Kiir and leaders in Khartoum about how to move forward and get the CPA back on track," he said. A week of clashes in May between northern government soldiers and former southern rebels resulted in almost 90,000 people in the area fleeing their homes, and at least 22 dead soldiers. Abyei lies just north of the disputed boundary line with southern Sudan in a volatile region that remains contested despite the peace agreement. It is coveted by both north and south because of its oil resources and green fields used for grazing cattle. The fighting in Abyei flared at the same time the UN was warning of a dangerous escalation of violence on another Sudanese front - the Darfur conflict. Earlier in May, a Darfur rebel group staged an attack just outside the capital Khartoum for the first time since that conflict in western Sudan began in 2003.