U.S. closely watching China's weapons development

Austin told reporters during a visit to the former Soviet republic of Georgia that Washington was closely watching "Chinese development of armament and advanced capabilities in systems that will only increase tensions in the region."

But Austin declined to comment on a report that Beijing had tested a nuclear-capable hypersonic missile.

The Chinese foreign ministry meanwhile stated that China had tested a space vehicle in July and not a hypersonic missile, as reported by the Financial Times.