Southeast Asian leaders began a virtual summit Tuesday, with Myanmar skipping the annual meeting in protest after its top general was shut out for refusing to cooperate in defusing the crisis in his country since the military takeover.

The exclusion of Senior Gen. Min Aung Hlaing was an embarrassment for Myanmars military and the harshest rebuke by the Association of Southeast Asian Nations since the military ousted civilian leader Aung San Suu Kyi and took over the government Feb. 1.

Brunei, who is this years chair of the 10-member bloc, invited Myanmars highest-ranking veteran diplomat, Chan Aye, as a non-political representative but she didnt attend the meeting, two diplomats said. The diplomats requested anonymity as they are not authorized to speak to the media.

Myanmars Foreign Ministry vowed late Monday to challenge ASEANs unprecedented move to downgrade its participation in the three-day summit, which is being held by video due to coronavirus concerns. It said it has informed Brunei that it can only accept participation by the general, who now heads Myanmars government and ruling military council, or a ministerial-level representative.

The talks will be joined by other world leaders including U.S. President Joe Biden and the leaders of China and Russia, and are expected to spotlight Myanmars worsening crisis and the pandemic as well as security and economic issues.

ASEANs sanctioning of Myanmar marked a shift from the bloc's bedrock principles of non-interference in each others domestic affairs and deciding by consensus. Myanmar cited the violation of those principles enshrined in the groups charter when it rejected ASEAN's ban on its military leader from the summit.

Myanmar's absence at the summit follows an impasse over ASEAN's envoy to Myanmar, Brunei Second Foreign Minister Erywan Yusof, who was denied permission by the military to meet with Suu Kyi and other government leaders detained since the Feb. 1 takeover.

ASEAN leaders agreed on a five-point contingency plan in an emergency meeting in April in Indonesia that was attended by Min Aung Hlaing. They called for an immediate end to violence in the country and the start of dialogue to be mediated by the ASEAN envoy, who should be allowed to meet all parties. But Myanmar's commitment to the plan is in doubt.

ASEAN has been under pressure to help end the crisis in Myanmar, where the militarys efforts to quash opposition have triggered increasingly violent and destabilizing resistance. Almost 1,200 civilians are estimated to have been killed by security forces. The government says a smaller number of people were killed and that security forces have acted to restore order amid what it describes as terrorism and arson.