The army chiefs of landlocked Ethiopia and the self-declared Republic of Somaliland have been discussing military cooperation as concern grows over a deal that could give Ethiopia a naval base on the Gulf of Aden.

The two sides signed a deal on January 1, recognized to give Ethiopia commercial and military access to the sea.

Somalia called it an act of aggression.

It considers Somaliland as part of its territory and has vowed to defend its sovereignty.

Somaliland, a former British protectorate, seceded from Somalia in 1991 but is not internationally recognised as an independent state.