US Secretary of State Marco Rubio on his first full day in office Tuesday warned jointly with Japan, India and Australia against coercive actions in Asia, in a veiled but clear warning to China over its actions at sea.

U.S. Secretary of State Marco Rubio met with counterparts from Australia, India and Japan on Tuesday, a meeting he said will stress the importance of working with allies "on the things that are important to America and Americans.

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.