An escalating conflict in Ethiopia’s restive Tigray region has killed hundreds of people, sources on the government’s side said, even as the prime minister sought on Monday to reassure the world his nation was not sliding into civil war. The flare-up in the northern area bordering Eritrea and Sudan threatens to destabilise Africa’s second most populous nation where ethnic conflict has already killed hundreds since Prime Minister Abiy Ahmed took over in 2018. Reuters reporters travelling in Tigray and the neighbouring Amhara region saw trucks packed with armed militia and pickups with machine guns mounted on the back rushing to the front line in support of the federal government push. Some militia members waved the Ethiopian national flag. Abiy, the continent’s youngest leader at 44, won a Nobel Peace Prize last year for democratic reforms and for making peace with Eritrea . But last week the prime minister, from Ethiopia’s largest ethnic group, the Oromo, launched a campaign against forces loyal to Tigrayan leaders whom he accused of attacking a military base in the town of Dansha. “Concerns that Ethiopia will descend into chaos are unfounded and a result of not understanding our context deeply,” he tweeted on Monday. “Our rule of law operation is aimed at guaranteeing peace and stability.” Abiy has said jets have been bombing arms depots and other targets. Aid workers and security sources have reported heavy fighting on the ground. A military official in Amhara, on the side of the federal troops, said that clashes with Tigrayan forces in Kirakir, near the Tigray-Amhara border, had killed nearly 500 Tigrayan forces. Three security sources in Amhara working with the federal troops said the Ethiopian army had also lost hundreds in the original battle in Dansha. Reuters has been unable to verify numbers, though a diplomat also said hundreds were believed to have died. The prime minister’s office and Ethiopia’s national army did not immediately respond to requests for comment. The Tigray People’s Liberation Front (TPLF), which governs the region, is battle-hardened from both the 1998-2000 war with Eritrea and the guerilla war to topple Mengistu Haile Mariam in 1991. TPLF forces and militia allies number up to 250,000 men and possess significant hardware, experts say. ‘No mercy’ Tigrayans account for just 5 per cent of Ethiopians but had, before Abiy’s rule, dominated politics since rebels from their ethnic group toppled Marxist military rule in 1991. They say Abiy’s government has unfairly targeted them as part of a crackdown on past rights abuses and corruption. “These fascists have demonstrated they will show no mercy in destroying Tigrayans by launching more than 10 air strike attempts in Tigrayan cities,” the TPLF said via Facebook. There was no immediate response from the prime minister’s office, or from the spokesman of the state of emergency task force established by the government. The army said it was intensifying attacks and that large numbers of Tigrayan special forces and militia were surrendering. It denied a TPLF claim of downing a jet. Abiy, a former soldier who fought alongside Tigrayans against Eritrea, has so far defied calls from the United Nations and others to negotiate. Journalists were turned away from the Dansha base on Monday by soldiers citing safety concerns. Outside the base, SUVs and pickups were filled with soldiers and a black metal sign read: “Let’s build one democratic country together”. Military helicopters flew northward. On a road into Dansha from the neighbouring Amhara region – which is backing the federal government – huts in a string of villages appeared abandoned. In some parts, men in plain clothes with AK-47s stood guard. A senior diplomat working on the Ethiopia crisis said Abiy had increasingly fallen back on support from Amhara – fuelling risk of more ethnic violence – after parts of the military’s Northern Command went over to Tigrayan control. “Ethiopia is like an empire crumbling before our own eyes,” the diplomat said. There are also fears of reprisals against Tigrayans elsewhere, with 162 people including a journalist arrested in Ethiopia’s capital Addis Ababa on Sunday on suspicion of supporting the Tigrayan forces. All-out war would damage Ethiopia’s economy after years of steady growth in the nation of 110 million people. It could also add to the hundreds of thousands displaced in the last two years.