The United Nations' Independent Investigative Mechanism for Myanmar (IIMM) on Tuesday said it had gathered swaths of evidence of human rights violations across Myanmar in the past 18 months.

The junta seized power on February 1 last year, ousting the civilian government and placing de facto leader Aung San Suu Kyi under arrest.

The IIMM — established by the UN Human Rights Council in 2018 to deal with Myanmar's preexisting domestic conflicts — seeks to collect evidence and prepare files for criminal prosecution on acts committed since 2011.

What does the report say?

The latest report includes a look at crimes committed since the coup in early 2021, which it says are on a shocking scale.

"Crimes have been committed in Myanmar on a scale and in a manner that constitutes a widespread and systematic attack against a civilian population," it said.

The authors said they had "collected a significant amount of information items, including videos, photographs and documents potentially indicative of crimes against humanity and war crimes committed across Myanmar by various individuals since February 2021."

"The scope of potential international crimes taking place in Myanmar has broadened dramatically," it said.

According to the IIMM, evidence suggests the transgressions included murder, torture, deportation, imprisonment and forcible transfer.

They also included rape and other forms of sexual violence, committed by members of the armed forces against women, children and members of the LGBT+ community.

It said the imposition of death sentences imposed on the basis of secret proceedings — as happened with four democracy activists in July — "could constitute the crime of murder, openly carried out by an organ of government."

Meanwhile, the authors said the information collected was against the backdrop of several armed conflicts on Myanmar's territory that were "ongoing and intensified."

The IIMM promised it would use the evidence to try to bring the perpetrators to justice.

"Perpetrators of these crimes need to know that they cannot continue to act with impunity," IIMM chief Nicholas Koumjian said in a statement. "We are collecting and preserving the evidence so that they will one day be held to account."

No progress on justice for Rohingya

The report pointed out that the month of August marks the five-year commemoration of the 2017 clearance operations in Rakhine State, which led to the displacement of nearly 1 million mainly Muslim Rohingya people.

"Tragically for the Rohingya and all the peoples of Myanmar, progress on ending impunity and ensuring accountability for crimes committed remains limited," the authors said.

Nobel Peace Prize laureate Suu Kyi, who was de facto civilian leader at the time, dismissed much of the criticism of the military as "unsubstantiated narratives," saying refugees may have exaggerated abuses.

The army has justified its power grab — which ended a decade of tentative steps toward democracy — by alleging massive fraud during the 2020 election. The vote saw Suu Kyi's National League for Democracy defeat a military-backed party.

Myanmar has faced turmoil ever since, with fighting across large parts of the country and the economy in freefall.

Edited by: Mark Hallam