The department has urged all armed actors to stop using violence against civilians and urged the authorities to investigate the allegations.

Last week, Human Rights Watch (HRW) said Tigrayan forces summarily executed dozens of civilians in “apparent war crimes” in two towns under their control in Amhara region.

Witnesses described to HRW investigators that they saw Tigrayan fighters in Chenna and Kobo villages kill a total of 49 civilians in separate incidents.

The executions occurred between 31 August and 9 September this year, the rights watchdog said.

It called on the UN to establish an international inquiry into war crimes and probe abuses by all parties in the conflict.

The US has also called for the cessation of hostiles and negotiations to start without any precondition.

The conflict erupted on 4 November last year when Ethiopia's government launched an offensive to oust the Tigray People's Liberation Front (TPLF) after its fighters captured federal military bases in Tigray.

Since then, the fighting has expanded to neighbouring regions of Amhara and Afar, forcing hundreds of thousands from their homes.

Recently, the Ethiopian military regained towns and cities previously controlled by Tigray militants in the Afar and Amhara areas.

Ethiopia's year-long conflict has created a massive humanitarian disaster, with thousands of people killed and at least nine million people in desperate need of help.