ADDIS ABABA - Ethiopia has agreed to work with the United Nations in delivering humanitarian aid to its Ogaden region, where a crackdown on rebels had impeded the flow of supplies, the United Nations said on Thursday.

The U.N. and Ethiopia's disaster preparedness agency will soon establish joint centres in the worst affected areas of the arid, ethnic Somali region to facilitate shipments of food, medicine and veterinary support, the U.N. said.

"The Ethiopian government has assured the U.N. that humanitarian activities within Somali region will be unrestricted," said Fidele Sarassoro, the U.N. Humanitarian Coordinator for Ethiopia.

Ethiopia had said it was clamping down on aid shipments to make sure they were going to the most-affected people and not Ogaden National Liberation Front (ONLF) rebels.

Ethiopia was working with the United Nations to make sure that all relief supplies "were properly monitored," the statement said.

The government has also offered to re-establish commercial flights to Kebridehar and Shilabo -- major towns in the region -- to facilitate the joint mission, the statement said.

Ethiopia had denied blocking food delivery to the Somali region where government forces and the rebel Ogaden National Liberation Front (ONLF) have been fighting for months.

Fighting in the Somali region had intensified after ONLF forces attacked a Chinese-run oil field killing nine Chinese workers and more than 60 Ethiopian soldiers and employees.

Ethiopia had said it had killed more than 500 rebels an captured 170 during offensive in the volatile but energy-rich region bordering Somalia.