Taking the next step in their dramatic diplomatic thaw, the leaders of Ethiopia and Eritrea on Tuesday officially opened the border where a bloody war divided them for decades, with emotional residents embracing after years of separation.Ethiopia's reformist new Prime Minister Abiy Ahmed and longtime Eritrean President Isaias Afwerki "marked the radical transformation of the Ethio-Eritrea border into a frontier of peace & friendship," Abiy's chief of staff Fitsum Arega said in a Twitter post.The leaders visited the Bure Front with members of their militaries to mark the Ethiopian new year and later did the same at the Serha-Zalambesa crossing, Eritrean Information Minister Yemane Meskel said on Twitter.Photos showed Abiy in camouflage walking alongside Isaias in olive drab, while a ribbon stretched across one border post bristled with military personnel carrying not guns but cameras. Hundreds of civilians waved the countries' flags. People of the countries' Tigray region, who share close cultural ties, danced while flag-draped camels wandered by.The former bitter rivals have made a stunning reconciliation since Abiy weeks after taking office in April announced that Ethiopia would fully embrace a peace deal that ended a 1998-2000 border war that killed tens of thousands. At the time, he said the countries would celebrate the Ethiopian new year together: "We want our brothers and sisters to come here and visit us as soon as possible."Embassies have reopened, telephone lines have been restored and commercial flights between the capitals have resumed as some long-separated families have held tearful reunions. Landlocked Ethiopia, one of Africa's fastest-growing economies, and Eritrea, one of the world's most closed-off nations, also plan development cooperation around Eritrea's Red Sea ports in particular.Reports on social media on Monday indicated that mine-clearing activities were underway in one border area, signaling that an opening was planned. The United Nations has called the border one of the world's most heavily mined.It was not clear if the countries would withdraw troops from the border.Abiy on Monday told a new year's eve concert crowd of thousands in Ethiopia's capital, Addis Ababa, that "as of today, Ethiopian and Eritrean people will prosper together and march in unison. ... The last five months have brought hope and reconciliation."The Ethiopian new year has roots in the Ethiopian Orthodox Church and is related to the Julian calendar. Eritrea has used the Gregorian calendar since it gained independence from Ethiopia in 1993.The reconciliation between Ethiopia and Eritrea has been warmly welcomed by the international community and has led to a series of further thaws in the fragile Horn of Africa region, with Eritrea resuming diplomatic ties with both turbulent Somalia and the small but strategic port and military nation of Djibouti.Observers now wonder whether the thaw will inspire Eritrea's leader, who has led since independence without elections, to embrace reforms and loosen a strict military conscription system that has led the small country to become one of the largest sources of migrants fleeing toward Europe, Israel and elsewhere.PM Abiy Ahmed and President Isaias Afwerki are visiting Bure Front along Ethio-Eritrea border to celebrate the New Year with members of the Ethiopian & Eritrean Defense Forces following the full normalization of the relations between the two countries. #Ethiopia #Eritrea pic.twitter.com/Z9C4QkNsPM— Fitsum Arega (@fitsumaregaa) September 11, 2018Road links between Ethiopia and Eritrea will be operational, opening the gate for cross border movement of people and goods. With fully normalization, our recent tragic history is coming to an end. #Ethiopia #Eritrea (2/2) pic.twitter.com/9BRYSeUlW1— Fitsum Arega (@fitsumaregaa) September 11, 20182 major Ethiopia-Eritrea borders have reopened after 20 years https://t.co/ewIgOLBN61 pic.twitter.com/Zo9KAERFnh— OkayAfrica (@okayafrica) September 11, 2018The land border between Ethiopia and Eritrea reopens after 20 years, clearing the way for trade between the former foes https://t.co/esh2Kuobzk pic.twitter.com/ae1HSlNlkn— TRT World (@trtworld) September 11, 2018 * Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.