Human Rights Watch and Amnesty International accused in a new report of widespread violations against civilians in the western part of the besieged Tigray region in Ethiopia, which amount to war crimes and crimes against humanity.

The human rights organizations said in the report issued on Wednesday that the crimes were committed by security officials and civil authorities from the neighboring Amhara region, sometimes "with the consent and possible involvement of Ethiopian federal forces."

The report stated that the violations are "part of an organized and widespread attack against the civilian population in Tigray, which amounts to crimes against humanity as well as war crimes."

In response, the Ethiopian federal authorities strongly denied the allegations that they deliberately targeted Tigray with violent attacks. 

They said at the outbreak of the war in November 2020 that their goal was to disarm the rebel leaders in Tigray. Ethiopian officials in the federal capital Addis Ababa and in Amhara did not respond to requests for comment on the allegations in the human rights groups' report.

The report, which was the result of an investigation lasting months that included more than 400 interviews, accused millions of inhabitants of Tigray of being forced to leave their homes in a violent campaign of unlawful killings, sexual assaults, mass arbitrary arrests, livestock looting, and deprivation of humanitarian aid.

Widespread atrocities have been reported in the Tigray war, where the Ethiopian government forces and their allies, including forces from neighboring Eritrea, face most of the charges. Fighters loyal to the Tigray leaders' party - the Tigray People's Liberation Front - have also been accused of committing violations as the war spreads to nearby areas. 

Amnesty International said in a report issued in February that fighters affiliated with the Tigray People's Liberation Front deliberately killed dozens of people, gang-raped dozens of women, and looted property over several weeks last year in the Amhara region.

The new report by Human Rights Watch and Amnesty International focuses on the attacks targeting Tigray in western Tigray and describes them as "ethnic cleansing," a term referring to the forced removal of populations from an area through expulsions and other acts of violence, including often killing and rape.

Among its recommendations, the human rights groups call for a "neutral protection force" in western Tigray, possibly with the deployment of an African Union-backed peacekeeping mission, "with a strong mandate to protect civilians." Their report also urged the UN Security Council to impose an arms embargo targeting all warring parties.