WASHINGTON — With breakneck speed, Ethiopia and Eritrea have resolved the decades-long conflict that had come to define the East African nations’ tumultuous 25-year relationship.

At the State Palace in Eritrea, President Isaias Afwerki and Ethiopian Prime Minister Abiy Ahmed signed a declaration of peace Monday, formally ending the state of war between their countries and setting the stage for a new era of harmonious relations.

Both countries stand to benefit from closer ties, and the scope of the peace deal’s potential implications emerged shortly after the leaders signed the document.

Monday’s agreement specifies that “transport, trade and communications links” will be re-established, and, as early as Sunday, the ability to make phone calls between the countries had been restored.

Commercial flights between the nations will resume next week, and plans to reopen embassies in the respective capitals are in the works.

Speaking at the African Union in Addis Ababa, United Nations Secretary General António Guterres said that U.N.-imposed sanctions against Eritrea “will naturally become obsolete” in the wake of normalized relations between the countries.

Sanctions were imposed in 2009 for Eritrea’s alleged assistance to al-Shabab. Last November, the U.N. determined that no evidence currently links Eritrea to the Somalia-based militant group.

Guterres cautioned, however, that the decision was not his to make, and the U.N. Security Council would need to review the matter before making a determination.

Also on Monday, Mahboub Maalim, the executive secretary of the East African trade bloc IGAD, said that he “looked forward to Eritrea rejoining the IGAD family.” Eritrea left the bloc in 2007 and was subsequently blocked from re-entering.

Eritrean reforms?

Michael Woldemariam, a political scientist and assistant professor at Boston University’s Pardee School of Global Studies, told VOA that the Eritrea-Ethiopia rivalry has contributed to security issues across the region, including Eritrea’s strained relationships with Djibouti and Sudan, and Ethiopia’s tensions with Egypt and Somalia.

“Taking that off the table now and getting the governments of both countries to work together is going to move the region as a whole forward in terms of cooperation — regional cooperation on security matters," Woldemariam predicted.

But the implications of the peace deal are less clear when it comes to a range of domestic issues in Eritrea, a former province of Ethiopia, Woldemariam said.

Eritrea seceded in 1991 after a 30-year war for independence and gained international recognition two years later. But it never fully emerged from the shadow of its conflict with Ethiopia, and the countries fought a border war from 1998 to 2000, followed by decades of cold war, proxy conflicts and, at times, open hostilities.

Ongoing conflict with its considerably larger neighbor made national defense Eritrea’s prime objective. Its constitution was never implemented, elections have never been held and all young people are conscripted into mandatory, open-ended national service.

Woldemariam called the peace deal “breathtaking,” but he said a “wait-and-see” approach is needed when it comes to Eritrea’s domestic policies.

“The optimist in me thinks that there may be some movement on these issues going forward,” Woldemariam said.

That could mean implementing the country’s constitution, opening political space, demobilizing people recruited into national service and releasing political prisoners.

Middle East connection

The Middle East has likely played a hand in the historic developments unfolding in the Horn of Africa. The United Arab Emirates is a mutual ally of both Eritrea and Ethiopia, and has both commercial and security considerations for bringing the countries closer together, Woldemariam said.

The UAE recently made a $1 billion cash infusion in the National Bank of Ethiopia and an additional $2 billion in investments in Africa’s second-most populous country.

The oil-rich nation has also collaborated with Eritrea on security efforts, including an Emirati base in Assab, a port city in southern Eritrea.

“This is somewhat speculative, but it’s hard not to think that the UAE didn’t play some sort of a role in the background in helping to bridge the divide between the two countries, and the same goes for the U.S. as well,” Woldemariam said.

Some have speculated that the United States has been mediating the peace deal for months. High-ranking U.S. and Eritrean diplomats have met several times since April, but the substance of those discussions isn’t clear.

Peace derailed?

With a formal peace deal now signed, a new chapter in Eritrea-Ethiopia relations appears all but certain. But fault lines remain.

“One concern, of course, would be resistance in some of the border regions to the implementation of the EEBC (Ethiopia-Eritrea Boundary Commission) decision,” Woldemariam said.

That decision, made in 2002, resulted in a definitive ruling about the border between the countries. Both sides agreed to accept the decision when they signed the Algiers Agreement, which ended the border war in 2000, but Ethiopia later reneged.

The current deal, Woldemariam said, involves a “three-player game” between not just Eritrea and Ethiopia but also Ethiopia’s federal government and the Tigray regional state. That region borders Eritrea, and some of its residents and political representatives feel they have been excluded from the process that’s unfolding, Woldemariam said.

But the peace process that’s now in motion, Woldemariam believes, has too much momentum to unravel.