China has returned the US-owned underwater drone it seized last week in the South China Sea, the Pentagon and China's defense ministry announced early Tuesday.
In a statement, Pentagon Press Secretary Peter Cook said China's seizure of the US Navy Ocean Glider Unmanned Underwater Vehicle was "inconsistent with international law" and the US would "continue to investigate the events surrounding the incident."
China said the drone was returned after "friendly consultations" between the two countries.
"After friendly consultations between the Chinese and U.S. sides, the handover work for the U.S. underwater drone was smoothly completed in relevant waters in the South China Sea at midday on Dec. 20," China's defense ministry said.
The incident took place about 50 nautical miles northwest of the Philippines on Thursday, Captain Jeff Davis, the director of press operations at the Defense Department, said in an emailed statement to BuzzFeed News.
China's defense ministry later said on Saturday it would return the drone, accusing the US of "hyping up" the incident. The announcement came after Beijing ignored requests to return the equipment to the crew of the research vessel that launched it.
The "ocean glider" — an underwater drone — was collecting data when the ASR-510, a Dalang III-class ship, approached the USNS Bowditch, Davis said.
A small boat deployed from the Chinese ship pulled the drone from the water and ignored the Bowditch's crew's demands for the drone's return when reached over bridge-to-bridge radio.
"We have since worked through diplomatic channels to demarche China on this," Davis said, using the formal term for a diplomatic demand given from one country to another. "This is not the sort of conduct we expect from professional navies."
"The [unmanned underwater vehicle (UUV)] is a sovereign immune vessel of the United States," Cook said. "We call upon China to return our UUV immediately, and to comply with all of its obligations under international law."
On Saturday, China released a one-sentence statement on the situation to the Associated Press.
"According to (our) understanding, the US and Chinese sides are working on appropriately handling this matter through channels between the two militaries," the foreign ministry said.
Later, however, the Chinese defense ministry released a statement from spokesman Yang Yujun, who said Beijing would return the vehicle.
"The Chinese side has decided to hand it over to the US in an appropriate manner," Yang said, adding that US statements on the incident were "not conducive to the smooth settlement of the problem."
"During this process, the US side's unilateral and open hyping up is inappropriate, and is not beneficial to the smooth resolution of this issue. We express regret at this," he said.
Yang said the drone was seized to ensure the “safe navigation of passing ships” in Chinese waters, but Beijing's claims to the territory are not recognized by most of the international community.
"China resolutely opposes [US military activity in the area] and urges the US to stop such activities," Yang said. "China will continue to be vigilant against the US activities and take the necessary measures to deal with it."
President-elect Donald Trump also weighed in on the situation on Saturday, tweeting "China steals United States Navy research drone in international waters - rips it out of water and takes it to China in unpresidented [sic] act." (He later deleted the tweet and replaced it with one fixing his spelling error).
Later Saturday, Trump sent another tweet saying China should "keep it."
The State Department did not immediately return a request for comment on the contents of the demarche.