A Chinese warship has seized an underwater drone deployed by a US oceanographic vessel to collect scientific data in the South China Sea, US officials said on Friday.
The seizure, that took place on December 15 in international waters about 50 nautical miles northwest of Subic Bay off the Philippines, has triggered a formal diplomatic protest and a demand for its return, US officials added.
The Pentagon confirmed the incident at a news briefing and said the drone used commercially available technology and sold for about $150,000.
The seizure took place a day after China's ambassador to the United States said Beijing would never bargain with Washington over issues involving its national sovereignty or territorial integrity.
A US research group this week said new satellite imagery indicated China has installed weapons, including anti-aircraft and anti-missile systems, on all seven artificial islands it has built in the disputed South China Sea.
Earlier this month, China had expressed "serious concern" after US President-elect Donald Trump said the United States did not necessarily have to stick to its long-held stance that Taiwan is part of "one China."
TRT World's Harry Horton is in Washington DC with more on this story.