China's navy has seized a U.S. underwater survey drone in international waters in the South China Sea, prompting a formal diplomatic protest and a demand for its return Friday, in a confrontation likely to exacerbate already rising tensions.

Thursday's seizure was the first of its kind in recent memory, and took place about 50 nautical miles (93 kilometers) from Subic Bay in the Philippines as the USNS Bowditch was about to retrieve the unmanned underwater vehicle (UUV).

The move coincided with a rise in saber-rattling from Chinese state media and its military establishment after U.S. President-elect Donald Trump criticized Beijing over the South China Sea and the nearly four-decade U.S. policy of viewing Taiwan as part of "one China."