The Ethiopian Human Rights Commission (EHRC) and the UN Office of the High Commissioner for Human Rights agreed Thursday to conduct a joint investigation into human rights violations and abuses allegedly committed by all parties involved in the ongoing conflict in Tigray, the northernmost region of Ethiopia.

The conflict in Tigray started on November 4 when Prime Minister Abiy Ahmed launched a military offensive after an Ethiopian National Defense Forces (ENDF) base was allegedly attacked by the Tigray People’s Liberation Front (TPLF), then the ruling party. A month later he stated that the conflict had ended. The ENDF is now pursuing TPLF leaders, who challenged his government’s legitimacy after the postponement of elections last year.

EHRC, an independent national human rights institution, published its preliminary findings Wednesday on grave human rights violations in Aksum, a city in central Tigray, in November. Aksum is part of the UNESCO World Heritage list. EHRC found that more than 100 civilians were killed by Eritrean soldiers. It said of the human rights violations that witnesses claimed were committed by the Eritrean military:

These widespread human rights violations are not ordinary crimes but grave contraventions of applicable international and human rights laws and principles, marked by intentionally directed attacks against civilians who were not directly taking part in the hostilities and including intentional looting, destruction and appropriation of property not justified by military necessity (including religious institutions and health facilities). As these grave human rights violations may amount to crimes against humanity or war crimes, it underscores the need for a comprehensive investigation into overall human rights situation in Tigray region.

Human Rights Watch and Amnesty International published similar reports of civilian killings in Aksum earlier this month.

Also on Wednesday, humanitarian non-governmental organization Doctors Without Borders stated that three of its staff members witnessed extrajudicial killings of at least four men by soldiers in Tigray.

Abiy acknowledged Tuesday that atrocities have been committed in Tigray. He admitted that Eritrean troops entered Tigray, and suggested their possible involvement in human rights abuses against civilians. Prior to this acknowledgment, both Ethiopian and Eritrean governments repeatedly denied Eritrean troops’ presence in Tigray.

Earlier this month US Secretary of State Antony Blinken described the human rights abuses in western Tigray as “ethnic cleansing,” and called for the Eritrean and Amhara forces to exit the region.