MYANMAR'S military has engaged in systematic human rights violations, many amounting to war crimes and crimes against humanity, the United Nations said on Tuesday, in its first comprehensive human rights report since last year's coup.

Security forces have shown a flagrant disregard for human life, using air strikes and heavy weapons on populated areas and deliberately targeting civilians, the U.N. High Commissioner for Human Rights, Michelle Bachelet, said.

Many victims were shot in the head, burned to death, arrested arbitrarily, tortured, or used as human shields, she said in a statement on the report, which urged "meaningful action" by the international community.

"The appalling breadth and scale of violations of international law suffered by the people of Myanmar demand a firm, unified, and resolute international response," Bachelet said.

Myanmar's military spokesperson did not answer calls seeking comment on the U.N. report on Tuesday.

The military says it has a duty to ensure peace and security. It has denied atrocities have taken place and has blamed "terrorists" for causing unrest.

The junta has failed to consolidate power since its overthrow of Aung San Suu Kyi's elected government in February 2021 triggered a backlash of a kind not seen in decades.

Western countries have imposed broad sanctions on the military and its businesses after anti-coup protests were lethally suppressed by troops, with thousands of people arrested and many prosecuted, including Suu Kyi, who has since been convicted of crimes that include incitement.

The U.N. report said it was based on interviews with scores of victims of abuse and witnesses, whose accounts were corroborated with satellite imagery, verified multimedia files and open-source information.

The army has met sustained resistance in the countryside from militias allied with the ousted government. The U.N. report said troops had carried out mass killings in the Sagaing region, with some victims found dead with their hands and feet tied.

In Kayah State, burned bodies of women and children were found, some in positions indicating they had tried to escape and were burned alive, it said.

The report found detainees were tortured during interrogation, including suspension from ceilings, electrocution, injection of drugs and some subjected to sexual violence, including rape.

The junta has in the past year scolded the U.N. and its independent experts for interference and what it calls reliance on distorted information from partisan groups.

The report also said at least 543 people had been killed for their perceived support of the military government.