Somalia and several Western countries have said Ethiopia's port deal has boosted Al Shabaab's recruitment efforts.
Somali President Hassan Sheikh Mohamud said his country would "defend itself" if Ethiopia goes ahead with a deal to set up a naval base in the breakaway region of Somaliland and possibly recognise the territory as an independent state.
Landlocked Ethiopia agreed a memorandum of understanding (MoU) on January 1 to lease 20 km of coastline in Somaliland - a territory that Somalia says it owns, even though the northern region has enjoyed effective autonomy since 1991.
Ethiopia said it wants to set up a naval base there and offered possible recognition of Somaliland in exchange - prompting a defiant response from Somalia and fears the deal could further destabilise the Horn of Africa.
Somalia and several Western countries, including the United States, which regularly carries out strikes against militants in Somalia, have said Ethiopia's port deal has boosted Al Shabaab's recruitment efforts.
Mohamud told Reuters that according to their intelligence sources, some of the new recruits are nationalists joining because of Ethiopia's recent port deal with Somaliland.