Military troops from Thailand, the United States, Japan, South Korea, Singapore, Indonesia and Malaysia gathered at Camp Akatosorot in Phitsanulok to take part in an opening ceremony held to mark the official start of Exercise Cobra Gold 2014.
The exercise is aimed at improving the ability of nations to conduct and plan joint military operations as well as to build relationships between member states.
In addition to the seven countries attending the drill, at least twenty more countries have sent observers to this year's drill, which is focused on humanitarian assistance in a conflict situation, as well as disaster relief.
Miss Kristie Kenney, US Ambassador to the Kingdom of Thailand, said Cobra Gold was the world’s largest and most successful multilateral military exercise.
Around 10,000 military personnel are taking part in this annual exercise, which continues until February 21.