July, but the Ethiopian Government has since then relaxed restrictions, and licensed the United Nations and 19 agencies to work there amid fears of a humanitarian crisis fuelled by the fighting.

Government sources said the pair had abused their position.

"The two foreigners were expelled because they were involved in an attempt to divert food aid to rebels," one said.

The worst-hit areas in the conflict have been the most difficult for aid workers to access.

Save the Children - which has been working in Ethiopia since 1932, and runs education, livestock and sanitation projects in Ogaden - gave no version of events.

But aid workers in Addis Ababa confirmed the pair's exit.

"They have been working in Ogaden on business visas, but were then refused additional work permits and asked to leave," said one humanitarian worker, who asked not to be named.