In the latest US-Chinese clash in the South China Sea, Washington formally requested that China return an unmanned underwater drone that its navy seized in worldwide waters Thursday.
Citing an anonymous US defense official, Reuters reports the seizure took place on December 15 just as usa oceanographic survey ship USNS Bowditch was about to retrieve the vehicle.
The Pentagon said the USNS Bowditch, an oceanographic survey ship, had two unclassified "ocean gliders" - unmanned underwater vehicles (UUVs) - in the water, conducting "routine operations in accordance with global law".
The vessel's seizure comes amid rising tensions in the South China Sea, where China has moved to fortify its claims to the region by building out tiny reefs into artificial islands. The waters where the incident occurred are known as the South China Sea.
A USA think tank reported this week that new satellite imagery indicated that China has installed weapons, including anti-aircraft and anti-missile systems, on all seven artificial islands it has built in the South China Sea.
The unmanned glider was collecting unclassified data in the South China Sea as part of a lawful military survey.
According to CNN, the Chinese warship was following the USNS Bowditch off the coast of Subic Bay to ensure that it wasn't spying. China later said the USA ship was operating illegally inside China's exclusive economic zone.
The U.S. didn't do much to decrease tensions when it was revealed that President-elect Donald Trump took a congratulatory phone call from Taiwan's president, Tsai Ing-wen, effectively violating the "One China policy".
The incident also could impact US diplomatic relations with the Philippines.
The Chinese Embassy said it had no immediate comment.
The incident is the latest in an increasingly tense relationship between China and the U.S. According to Reuters, an underwater USA drone that was "deployed by an American oceanographic" was taken by a Chinese Navy warship on December 15.
"The only thing they said after they were sailing off into the distance was: "we are returning to normal operations", Davis said". The president-elect broke with decades of USA policy in accepting a congratulatory phone call from Taiwanese President Tsai Ing-wen earlier this month.
He did not specifically mention Taiwan, or Trump's decision to accept a telephone call from Taiwan's president on December 2.