Southeast Asian foreign ministers gather in Cambodia's capital Phnom Penh for their annual meeting.

The ASEAN bloc had invited Myanmar to send a "non-political representative", citing a lack of progress on a consensus agreed last year to facilitate dialogue with opponents of the coup. That represented a rare rebuke from the organisation, long seen as a toothless talking shop, but which has sought to lead diplomatic efforts to tackle the Myanmar crisis.

However, Myanmar's junta on Monday said it would not attend after the bloc's "regrettable" exclusion of its top diplomat.