Myanmar will take part in the annual Cobra Gold US-Thai military exercise next year for the first time as an observer, a source at the Defence Ministry said.
The decision to invite Myanmar to join the military drill was reached shortly after US President Barack Obama won a second term in office last week. Mr Obama is visiting Myanmar later this month. The trip, the first time a US president will visit the country, is part of a Southeast Asia tour that will also include stops in Thailand and Cambodia.
According to the source, Thailand had been lobbying for some time for Myanmar to take part in the annual drill.
The next Cobra Gold exercise is tentatively scheduled for Feb 11-23.
The Myanmar observers will participate in the humanitarian assistance/disaster response and military medical portions of the exercise.
Cobra Gold has two categories of observers. The first is the "multinational planning augmentation teams", including nations like Singapore, Japan, South Korea, Malaysia and Indonesia.
Myanmar falls into the second category, known as "coalition observer liaison teams". The 2012 Cobra Gold had such teams from Brunei, China, the Netherlands, Laos, New Zealand, Russia, South Africa, Sri Lanka and the United Arab Emirates.
Foreign Ministry spokesman Manasvi Srisodapol said Mr Obama would arrive in Bangkok next Sunday in the afternoon and will stay overnight before heading to Phnom Penh to attend the East Asia Summit. Before Mr Obama's visit, US defence secretary Leon Panetta will visit Thailand on Thursday as a guest of Defence Minister ACM Sukumpol Suwanatat.
Mr Panetta is also scheduled to meet the leaders of the three branches of the armed forces during his visit.
Defence spokesman Thanathip Saengsawang said ACM Sukumpol is expected to sign a strategic partnership agreement with the US and a military support agreement in which Thailand will procure weapons from the US at discounted rates under the Excess Defence Article (EDA) programme.
He insisted Nasa's aborted weather-research project, which was to be based in Thailand, would not be brought up during the meeting.
After Thailand, the US defence secretary will travel to Cambodia to attend the Asean Defence Ministerial Meeting in Siem Reap.