Ethiopia has been an independent nation – apart from a few years of rule by fascist Italy – since 1868 while Sudan became independent in 1956. Both have lost chunks of territory – Eritrea seceded from Ethiopia in 1991 and South Sudan gained its independence in 2011.
The US ambassador to the United Nations and the UN's special envoy for Sudan have both voiced concerns at tensions between Sudan and Ethiopia, who have clashed in recent months over the Fashaga Triangle.
Volker Perthes, the special envoy and head of the United Nations Integrated Transition Assistance Mission in Sudan (UNITAMS), said 70,000 people had crossed the border into Sudan in recent months flying fighting in Ethiopia's Tigray region.
Ethiopia's Prime Minister Abiy Ahmed sent his troops into Tigray in November to crush the Tigray People's Liberation Front (TPLF), which had ruled the whole country between 1991 and 2012 but gradually lost their grip after the death of prime minister Meles Zenawi.
The conflict in Tigray, which also drew in neighbouring Eritrea, has caused great instability in the region, including along the border with Sudan.
On Wednesday, 10 March, Ms Thomas-Greenfield criticised “recent bellicose rhetoric” and the “positioning of additional forces around the el-Fashaga area” and warned both side “the risk of miscalculation is high.”
But what is the Fashaga Triangle and why is it suddenly a cause of friction…
