China seizes US Navy vehicle in international waters of South China Sea

China's navy has seized an unmanned, underwater vehicle (UUV) from the U.S. Navy in the disputed South China Sea, Reuters reported Friday.

The vessel seized by a Chinese warship in international waters was an American oceanographic drone, Reuters said. The drone was reportedly used to test water salinity and temperatures.

The vessel was "stolen by a Chinese warship literally right in front of the eyes of the American crew," according to CNN, which spoke to a U.S. defense official.

The incident took place on December 15.

The Chinese warship had been shadowing the USNS Bowditch before taking the drone, that official said.

"The UUV was lawfully conducting a military survey in the waters of the South China Sea," a U.S. official told Reuters. "It's a sovereign immune vessel, clearly marked in English not to be removed from the water - that it was U.S. property."

The drone was seized about 50 miles off Subic Bay.

The United States has formally requested the underwater drone be returned.

Beijing claims almost the whole of the South China Sea as its own.