Somali President Hassan Sheikh Mohamud has accused Ethiopia of trying to annex part of his country’s territory by signing a sea access deal with the breakaway region of Somaliland.

Speaking at the African Union summit in Ethiopia’s capital, Addis Ababa on Saturday, Mohamud also said Ethiopian security forces tried to block his access to the summit amid a dispute between the two countries.

He further pointed out that the agreement between Ethiopia and Somaliland signed on January 1 is nothing more than annexing part of Somalia to Ethiopia, and changing the borders of Somalia.

As part of the deal, signed by Ethiopian Prime Minister Abiy Ahmed and Somaliland’s leader Muse Bihi Abdi, Somaliland grants Ethiopia a 50-year lease on a naval base with access to Somaliland’s Berbera port for commercial marine operations. Neither side has made the terms of the deal public, but it appears to give Ethiopia the right to build a port in Somaliland in exchange for recognition.

Somaliland has enjoyed de facto independence for three decades, but Somalia considers the self-governing region and its four million people to be a part of its northern territory.

Mogadishu regards any international recognition of Somaliland as an attack on Somalia’s sovereignty, and the Somali government has called the port deal with Addis Ababa outrageous and unauthorized.

He claimed senior officers from Ethiopia’s military were in Somaliland preparing the ground for the territory’s annexation.  Somalia has suggested it would be prepared to go to war to stop Ethiopia from building a port in Somaliland. But Ethiopia’s Abiy has played down fears of an armed conflict over the Somaliland deal, telling lawmakers earlier this month that he had no intention of going to war with Somalia.