Leaders of Australia, India, Japan and the United States expanded joint security steps in Asia's trade-rich waters as outgoing U.S. President Joe Biden hosted counterparts from the Quad grouping established due to shared concerns about China.

President Joe Biden is convening the leaders of Australia, India and Japan for a Quad summit in his hometown of Wilmington, Delaware, this weekend, aiming to put a final stamp on an alliance he hopes will endure beyond his presidency.

CLAYMONT, Del. -- President Joe Biden told Indo-Pacific allies on Saturday that he believes China's increasing military assertiveness is an effort to test the region at a turbulent moment for Beijing.