Cambodian foreign minister Prak Sokhonn will make his second trip to Myanmar from Wednesday, a spokesman for his ministry said, as part of the junta’s peace commitment with the 10-member Association of Southeast Asian Nations (Asean).

Suu Kyi, who has been on trial accused of at least 20 crimes since a coup against her elected government last year, has been moved to a prison in the capital Naypyitaw and kept in solitary confinement. She denies all charges.

The 77-year-old had until last week been spared jail and was held in an undisclosed location, despite having several convictions for relatively minor offences.

Prak Sokhonn in a letter to the junta urged compassion.

“Aung San Suu Kyi is regarded internationally and by many in Myanmar as having a critical role in your country’s return to normalcy and national reconciliation through a peaceful political solution,” he wrote, according to a statement.

Activists denounced Prak Sokhonn’s last visit in March as a failure that favoured the junta and overlooked its opponents, criticism that he said he understood.

In his letter, he said a successful peace process was impossible with one side excluded.

“A peaceful political resolution to a conflict, no matter how complex it is, must involve the sharing of political space by all involved,” he added.