The head of the U.S. military's Pacific command called China a disruptive power in the Indo-Pacific region on Thursday and urged countries in the area to build capabilities and work together to ensure free and open seas.

Admiral Harry Harris, known for his combative views on Beijing's South China Sea expansion, was speaking at a security conference sponsored by the Indian government, where he was joined by the chief of staff, joint staff of Japan and the head of the Indian navy.

The three countries — the United States, Japan and India — have grown increasingly concerned about China's assertive military posture in the region and sought to draw closer, with Australia, in a "quad" of liberal democracies.