The U.N. human rights chief says Ethiopia's yearlong war has been marked by "extreme brutality" as a joint investigation into alleged atrocities faults all sides for committing abuses.

The report released Tuesday, conducted by the Ethiopian Human Rights Commission (EHRC) and the U.N Human Rights Office, details allegations of war crimes that have been committed in the war that broke out a year ago Thursday.

The investigation was hampered by authorities' intimidation and restrictions and didn't visit some of the war's worst-affected locations.

According to the BBC, thousands of people have been killed in the war, and millions have been displaced.

CNN reports that the report did not blame atrocities on a single party involved in the war.

"There are reasonable grounds to believe all parties to the conflict...either directly attacked civilians and civilian objects, such as houses, schools, hospitals, and places of worship, or carried out indiscriminate attacks resulting in civilian casualties and destruction or damage to civilian objects," the report states, according to the BBC.

Africa's second-most populous country is in a new state of emergency as rival Tigray forces threaten the capital.