A rocket attack by Tigray forces on Eritrea marks a major escalation of violence as thousands of Ethiopian refugees continue to pour into Sudan. The UN refugee agency says that over 20,000 people have crossed into Sudan from Ethiopia’s northern region, where federal government troops are battling forces loyal to the Tigray People’s Liberation Front (TPLF), the party of the regional government. The conflict, which has spilled over Ethiopia’s borders, threatens to destabilise the wider Horn of Africa region. The latest two-week war has killed hundreds of people. Ethiopia and Eritrea agreed in 2018 to end decades of hostilities, resulting in Ethiopian prime minister Abiy Ahmed winning the 2019 Nobel Peace Prize. However, there is still a deep-seated animosity between Eritrea and the battle-hardened TPLF over the border conflict.