Three Myanmar military officers were found guilty by a court martial investigating atrocities against Rohingya Muslims in conflict-ridden Rakhine state, the army announced Tuesday.

The rare action against military members came as Myanmar faces charges of genocide at the United Nations' top court over a brutal 2017 crackdown against the Rohingya.

Some 750,000 Rohingya fled to neighbouring Bangladesh with accounts of widespread murder, rape and arson.

Rights groups accused security forces of committing atrocities in various villages, including Gu Dar Pyin, where they alleged at least five shallow mass graves had been found.

Estimates from survivors in Bangladesh put the death toll in the hundreds.

After initially denying the allegations, the military started court martial proceedings in September, admitting there had been "weakness in following instructions" in the village.

The commander-in-chief's office announced Tuesday the court martial had "confirmed the guilty verdict" and sentenced three officers.

No details were provided on the perpetrators, their crimes, or sentences.

Rights groups Amnesty International called the lack of transparency on the court martial "alarming".

Hundreds of thousands of Rohingya fled to Bangladesh to escape a military crackdown in Myanmar
Hundreds of thousands of Rohingya fled to Bangladesh to escape a military crackdown in Myanmar AFP / Dibyangshu SARKAR

"Closed door trials shrouded in secrecy, and marred by a lack of independence in the military judiciary system, are not the way to end military impunity in Myanmar," said Amnesty's Ming Yu Hah.

The government has largely supported the army's justification of the 2017 operations as a means of rooting out insurgents.

Civilian leader Aung San Suu Kyi admitted at the International Court of Justice in December, however, that disproportionate force may have been used.

The military has maintained any atrocities were committed by a few maverick individuals.

UN investigators also found evidence of extrajudicial killings in other Rakhine villages, Maung Nu and Chut Pyin.

The army chief's office said Tuesday a court of inquiry would "continue to investigate" events at both villages.

In 2018 the military sentenced members of the security forces to a decade in prison for the killing of 10 Rohingya in Inn Din village, but they were released after serving less than a year.

Two journalists who exposed the massacre were detained for more than 16 months before they were pardoned following global outcry.

The state remains a flashpoint of ethnic and religious tensions, and the military has been locked in battle since January last year with insurgents fighting for more autonomy for ethnic Rakhine Buddhists.

Intensified fighting over the weekend drew alarm from the UN on Sunday, who called for both sides to respect international humanitarian law as thousands more civilians fled their homes from artillery shelling.