"The two countries will establish diplomatic relations and exchange ambassadors," said a "joint declaration on brotherly relations" signed in Asmara by Eritrean President Isaias Afwerki and Somali counterpart Mohamed Abdullahi Mohamed.

Mohamed's three-day visit to Asmara coincides with an extraordinary peace process between Eritrea and Ethiopia -- part of dizzying change in a region burdened by war, proxy conflicts, isolation and iron-fisted rule.

Once close, Somalia and Eritrea fell out over a decade ago as Asmara stood accused of backing militants on Somali soil in a proxy war with Ethiopia.

Eritrea long denied this, but was slapped with U.N. sanctions over its alleged backing of Al-Shabaab in 2009.

"Eritrea strongly supports the political independence, sovereignty and territorial integrity of Somalia as well as the efforts of the people and government of Somalia to restore the country's rightful stature and achieve the lofty aspirations of its people," read the declaration.

The document, posted on Eritrea's information ministry website, also said the two nations "will endeavor to forge intimate political, economic, social, cultural as well as defense and security cooperation."

They will in addition "work in unison to foster regional peace, stability and economic integration."