The meeting, bringing together representatives of the four largest militaries in the Indo-Pacific, was a clear signal that the Trump administration will intensify military preparations and threats directed at China.

Rubio called China the "most potent, dangerous adversary" during his confirmation and is expected to work with India, Japan, and Australia to counter this.

On his first full day as secretary of state, Marco Rubio is meeting with his counterparts from a group of countries known as the Quad: the United States plus India, Japan and Australia, representing nearly 2 billion people and more than a third of global GDP.