China is now deeply suspicious of any US military activities in the South China Sea. Photograph: (DNA)
The US says the drone was being operated by civilian contractors collecting unclassified scientific data in international waters.
China has returned to US an unmanned underwater drone that was seized by the Chinese Navy last week in international waters, the Pentagon press reports.
China's Defence Ministry said on Tuesday, the drone was handed back after "friendly consultations".
The seizure of the drone triggered speculations as well as a diplomatic protest about whether this will strengthen US President-elect Donald Trump's hand as he seeks a tougher line with Beijing.
The US says the drone was being operated by civilian contractors collecting unclassified scientific data in international waters. Officials say a noncombat ship was recovering two drones when a Chinese ship approached, launched a small boat and picked up one of them, according to the ABC news.
This has added to the concerns of US regarding China's growing military presence and aggressive posture in the disputed South China Sea, including its militarization of maritime outposts.
The US Navy has about 130 such underwater drones, made by Teledyne Webb, each weighing about 60 kg (130 pounds) and able to stay underwater for up to five months. They are used to collect unclassified data about oceans, including temperature and depth. They are used around the world, but it is unclear how many are used in the South China Sea, reports Reuters.
China is now deeply suspicious of any US military activities in the South China Sea.
While the state media and experts say that the use of the drone was likely part of US surveillance efforts in the disputed waterway.