Ethiopia has told six Norwegian envoys to leave the country, citing "dissatisfaction" over Norway's conduct in the Horn of Africa region, a Norwegian official says.

Norway was given a month's notice to withdraw the diplomats by September 15.Jonas Gahr Stoere, the Norwegian foreign affairs minister, said "we are surprised and regret the Ethiopian authorities' unilateral decision", but said the expulsion of the diplomats did not imply a break in diplomatic relations with Ethiopia.

Stoere on Monday said his ministry was unable to get any clarification from its Ethiopian counterpart on the reasons for the order.

"We must now take the consequences of the fact that the Ethiopian authorities are upholding their decision and we are therefore making preparations to withdraw six diplomats from our embassy in [the Ethiopian capital] Addis Ababa," he added.