Myanmar's army has "killed and injured civilians in indiscriminate attacks since January 2019" as it battles the Arakan Army, a well-trained guerrilla force from the Buddhist ethnic group seeking autonomy for Rakhine, Amnesty said in a report released on Wednesday.

It accused the military of carrying out "extrajudicial executions, arbitrary arrests, torture and other ill treatment, and enforced disappearances."

But it also said the Arakan rebels had committed abuses against civilians, including kidnappings, though on a lesser scale.

"The new operations in Rakhine state show an unrepentant, unreformed and unaccountable military terrorising civilians and committing widespread violations as a deliberate tactic," Nicholas Bequelin, regional director for East and Southeast Asia at Amnesty International, said.

The group said it had written to top Myanmar government and military officials with specific questions but had not received a reply.

Rakhine is best known for a brutal counterinsurgency campaign launched by the military in 2017 against the Rohingya, which caused more than 700,000 to flee to neighbouring Bangladesh. The army and other security forces were accused of abuses including organised rape, murder and village burning.

Critics including UN experts have accused the Myanmar forces of ethnic cleansing, and possibly even genocide.

The government insists it was engaged in acceptable military operations after Rohingya guerrillas carried out attacks on police.

While Rohingya insurgents have been largely inactive since late 2017, the Arakan Army has been engaged in increasingly fierce fighting with government forces since last year. The group seeks autonomy for the region.

Amnesty International said it uncovered evidence of new abuses carried out by units implicated in previous atrocities.

The government declared the Arakan Army a terrorist organisation after it killed 13 police officers and wounded nine in attacks on January 4.

Australian Associated Press