The African Union and US have called for the respect of Somalia's sovereignty and territorial integrity, in response to a controversial deal that landlocked Ethiopia struck with Somaliland for sea access.

The deal has caused diplomatic tension, with Somalia condemning it as an act of aggression and violation of its sovereignty and vowing to challenge it "by any legal means".

Somaliland seceded from Somalia in 1991 but is not internationally recognised as an independent state.

US Department of State spokesperson Matthew Miller on Wednesday said that "the United States recognises the sovereignty and territorial integrity of the Federal Republic of Somalia within its borders".

AU Commission chair Moussa Faki has also urged for the respect of the "unity, territorial integrity and full sovereignty...of Somalia and Ethiopia".

Both the US and AU have also asked the involved parties to pursue diplomatic dialogue to peacefully resolve the row, amid concerns that the deal could escalate tensions in the Horn of Africa region.