A large-scale military training exercise began Monday in northern Thailand involving 13,000 personnel from the United States and six Asian countries — Japan, South Korea, Indonesia, Malaysia, Singapore and the host nation.

Adm. Samuel Locklear, commander of the U.S. Pacific Command, said at an opening ceremony held in the northern Thai city of Chiang Mai that the annual exercise is a demonstration of the commitment of the participating countries to pursuing peace and stability in the region.

The exercise, code-named Cobra Gold 2013, covers both combat training and disaster relief. It will last until Feb. 21.

Highlighted drills include amphibious landing, jungle warfare, civilian evacuation and responses to chemical, biological and nuclear attacks.

This year, Myanmar for the first time joined the 20 other countries in the region to observe the exercise taking place at various locations in northern and eastern Thailand.

The United States invited Myanmar to take part in Cobra Gold 2013 as an incentive to the government of Myanmar President Thein Sein to continue its reforms.

Cobra Gold began in 1982 as a bilateral military exercise between Thailand and the United States. It developed into a multilateral affair in 2000 when Singapore was invited to join the annual drill.