Warships and aircraft from the four “Quad” nations, including Japan, kicked off the annual Malabar joint military exercise in the Bay of Bengal on Tuesday, with Australia rejoining the drills for the first time in 13 years.

The exercise comes less than a month after a highly symbolic Quad meeting in Tokyo of the top diplomats of four of the most powerful democratic countries in the Indo-Pacific region — Japan, Australia, India and the United States. Although few concrete takeaways emerged from those talks, they were widely interpreted as a message to China.

The exercise are not formally linked to the Quad forum, but observers say the participants hope to turn drill into a counterweight to Beijing’s increasingly potent military and political influence in the region.