Local media, citing military junta spokesman Zaw Min Tun, reported on Wednesday that the reason for the move was concern for the 78-year-old's health in view of the high temperatures in the capital Naypyidaw, where Suu Kyi was being held.

It was not certain whether she had been taken to another prison or transferred to house arrest.

The junta had not informed Suu Kyi's lawyers of the plan or of her new location, a source close to the prison authorities told dpa news agency.

In addition to Suu Kyi, former President Win Myint, who had been detained in a prison about 100 km south of the capital, has also been transferred.

On Wednesday, more than 3,000 prisoners were also released on the occasion of the Thingyan New Year festival, the military junta announced.

The army ousted and arrested the democratically-elected de-facto head of government Suu Kyi following a coup in February 2021.

A court controlled by the junta later sentenced her to a total of 33 years in prison for numerous alleged crimes.

Win Myint was sentenced to 12 years in prison.

In 2023, the military junta reduced Suu Kyi's sentence by six years and Win Myint's sentence by four years.

Myanmar plunged into chaos and violence following the army's takeover.

The junta is coming under increasing pressure politically and also militarily, with rebel groups involved in violent resistance against its rule.