(Recasts, summit ends) By Salah Sarrar TRIPOLI, Nov 21 (Reuters) - Six African leaders on Tuesday pledged to redouble Darfur peace efforts and repair frayed ties between neighbours Sudan and Chad, whose border region has been destabilised by violence in Darfur, a Libyan official said. Ali Treki, Secretary for African Union (AU) Affairs at the Libyan Foreign Ministry, told reporters a one-day mini-summit of leaders of Central African Republic, Chad, Egypt, Eritrea, Libya and Sudan agreed to "exert all efforts" for Darfur peace. He said Sudanese President Omar Hassan al-Bashir had extended separate invitations to Chadian President Idriss Deby and Central African Republic President Francois Bozize to visit Khartoum in an attempt to stem regional instability. Sudan and Chad have long accused each other of backing rebel groups operating on either side of the border. But in recent months the Darfur conflict has begun to spill a dangerous new mixture of refugees, rebels, militia and bandit raiders over Sudan's western borders into Chad and Central African Republic. Chad and Sudan agreed at a summit mediated by Libyan leader Muammar Gaddafi in Tripoli in February to stop insurgents setting up bases on their territories and end propaganda against one another. But Chad has continued to accuse Sudan of sending Janjaweed militia across the frontier and of arming and directing rebels trying to overthrow Deby. Sudan's government denies this. Chad announced plans this month to send troops to help Central African Republic confront violence stemming from Darfur. Deby said he hoped Tuesday's summit had helped. "This is the latest of many times I have visited Tripoli to talk about Chad and Sudan," he told reporters. "Unfortunately the Tripoli agreement was not implemented. We witnessed hostilities on the border. We witnessed the export of the communal war in Darfur to Chad." "I leave today hoping that this time it is for real." Mostly non-Arab rebels took up arms in Darfur in early 2003 accusing the government of marginalising the remote west. Khartoum mobilised militias to quell the revolt. Those militias stand accused of atrocities against civilians being investigated by the International Criminal Court. Washington calls the rape, murder and pillage in Darfur genocide, a charge Khartoum rejects. Treki said the leaders had agreed to continue to try to expand the Darfur peace agreement concluded in Abuja in May to include all factions and end the current crisis. Libyan and Egyptian officials say the six leaders want the Darfur rebel group, the National Redemption Front (NRF), to sign the May accord between Khartoum and another rebel group. The NRF is an alliance of Darfur rebel groups that rejected as inadequate the May peace accord. It says it is ready to negotiate with Khartoum but wants a new agreement.
