Soldiers from the U.S., Indonesia and five other nations are participating in a combat exercise on Indonesia’s main island of Java amid concerns about China’s aggression.

Soldiers from the U.S., Indonesia and five other nations began annual training exercises Thursday on Indonesia’s main island of Java while China’s increasing aggression is raising concern.

American and Indonesian soldiers have held the live-fire Super Garuda Shield drills since 2009, and Australia, Japan and Singapore joined last year. The United Kingdom and French forces are participating in this year’s exercises, with a total of about 5,000 personnel.

China sees the expanded drills as a threat, accusing the U.S. of building an Indo-Pacific alliance similar to NATO to limit China’s growing military and diplomatic influence in the region.

Brunei, Brazil, Canada, Germany, India, Malaysia, Netherlands, New Zealand, Papua New Guinea, Philippines, South Korea, and East Timor also sent observers to the two-week exercises in Baluran, a coastal town in East Java province.