China has accused the US of “hyping-up” an incident in which its navy seized a US underwater drone in international waters in the South China Sea.
The Pentagon said the drone was being used to carry out scientific research and must be returned – and warned China that this must not happen again.
It later said it had “secured an understanding” with the Chinese on the return of the vessel.
US President-elect Donald Trump accused the Chinese of “stealing”.
The incident is among the most serious military confrontations between the two powers for decades.
On Saturday, China’s Chinese defence ministry criticised the US, saying it had overreacted to the incident.
That statement came hours after a tweet by the US president-elect, in which he accused the Chinese of “stealing”.
Mr Trump had already inflamed the Chinese by speaking on the phone earlier this month with the leader of Taiwan, breaking a long-standing US practice on the China-Taiwan dispute.
Mr Trump drew criticism online for misspelling the word unprecedented – the latest in a series of errors in his Twitter posts. He has now corrected the entry.
A Chinese Navy ship pulled the unmanned drone from the water – just before the USNS Bowditch, and oceanographic research ship was about to retrieve it on Thursday.
The US made formal diplomatic complaint to China.
The drone was seized 92km (57 miles) north-west of Subic Bay near the Philippines in the South China Sea. The US said the unmanned drone was being operated by civilian contractors to conduct oceanic research.
China has claimed territorial rights over parts of the region but its claims are disputed. It is not clear if China claims the territory in which the drone was seized.
‘A remarkably brazen violation’
Observers said the seizure of the drone was the most significant military incident between the two countries since a 2001 mid-air collision between a US Navy surveillance aircraft and a Chinese fighter jet that led to the death of a Chinese pilot.
The seizure will likely add to US concerns about the growing military build-up by China in the South China Sea.
A US think tank reported this week that aerial imagery shows that China has installed weaponry along seven artificial islands they have built at sea, despite US protests.