An escalating conflict in Ethiopia’s restive Tigray region has killed hundreds of people, sources on the government side say, even as the prime minister sought to reassure the world his country 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 country, 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 mounted machine-guns rushing to the front line in support of the federal government push.

Some militia members waved the Ethiopian flag.

Mr 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, who is 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.”

Mr 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, told Reuters that clashes with Tigrayan forces in Kirakir had killed nearly 500 on the Tigrayan side.

Three security sources in Amhara working with federal troops said the Ethiopian army had also lost hundreds in the original battle in Dansha.

The Tigray People’s Liberation Front, which governs the region, is battle-hardened from both the 1998-2000 war with Eritrea and the guerrilla war to topple dictator Mengistu Haile Mariam in 1991.

TPLF forces and militia allies number up to 250,000 men and possess significant hardware, experts say.

Tigrayans account for just 5 per cent of Ethiopians but had, before Mr Abiy’s rule, dominated politics since rebels from their ethnic group toppled Marxist military rule in 1991.

They say Mr Abiy’s government has unfairly targeted them as part of a crackdown on past rights abuses and corruption.

-AAP