BEIJING: The United States (US) military will continue to operate "wherever" international law allows, including in the South China Sea, a top US admiral said in Beijing on Tuesday, a week after America infuriated China by sailing close to artificial islands it is building in the contested waters.

The US Navy's challenge last week to China's sovereignty claims in the South China Sea was not designed as a military threat, the head of US Pacific military forces said Tuesday in a mostly upbeat speech about prospects for preventing US-China disputes from escalating to conflict.

"International seas and airspace belong to everyone and are not the dominion of any single nation," Admiral Harry Harris said, according to prepared remarks for a speech at the Stanford Center at Peking University.

"Our military will continue to fly, sail, and operate whenever and wherever international law allows. The South China Sea is not — and will not — be an exception," he added.

Harris is the commander of the US Pacific Command and his public declaration in the Chinese capital is a mark of US resolve over the strategically vital waterway, where Beijing has built up rocks and reefs into artificial islands with facilities for military use.

Beijing claims sovereignty over almost the whole of the sea on the basis of a segmented line that first appeared on Chinese maps in the 1940s.

Harris described the claim as "ambiguous" and based on "the so-called 9-dash line".

Washington has repeatedly said it does not recognise Chinese claims to territorial waters around the artificial islands.

The USS Lassen guided missile destroyer sailed within 12 nautical miles of at least one of the land formations in the disputed Spratly Islands last week.

Harris tempered his comments with conciliatory remarks, praising US-China ties and pointing out that Chinese and American ships were visiting ports in each others countries.

"Some pundits predict a coming clash between our nations. I do not ascribe to this pessimistic view," Harris said, according to a copy of his speech.

"While we certainly disagree on some topics — the most public being China's claims in the South China Sea and our activities there — there are many areas where we have common ground."

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