China on Monday rejected US President-elect Donald Trumps claim that it had "
Beijing's seizure of the marine probe in international waters in the South China Sea raised already heightened tensions between the world's two largest military powers.
On Sunday, after Beijing and Washington announced the drone would be returned, Trump tweeted: "We should tell China that we don't want the drone they stole back. - let them keep it!"
China objected to Trump's accusation that it had stolen the drone, foreign ministry spokeswoman Hua Chunying said Monday, adding the claim was "not accurate".
"Imagine that you found something on the street -- you would need to first check and verify it before handing it back to someone else," she told a regular press conference.
Hua said the two sides "are in smooth communication through military channels, and we believe the incident will be properly handled". She gave no further details.
The Pentagon said Friday that a Chinese naval vessel "unlawfully" grabbed the unmanned underwater vehicle around 50 nautical miles northwest of Subic Bay in the Philippines.
China said the drone had been snatched since it might pose a safety hazard to other vessels.
It also said it "strongly opposed" US reconnaissance activities and had asked Washington to stop them.
The US said the device was collecting information on water temperatures, salinity and sea clarity.
In an earlier misspelled tweet Saturday, Trump also accused Beijing of theft.
"China steals United States Navy research drone in international waters?rips it out of water and takes it to China in unpresidented act," he wrote.
The state-owned China Daily rejected the claim in an editorial.
"What is truly amazing about this tweet, was the soon-to-be US president completely misrepresented what had actually happened -- that is more dangerous than funny," it said.
Trump's behaviour "could easily drive China-US relations into what Obama portrays as 'full-conflict mode'," it added, next to a cartoon that depicted Trump riding a bull into a china shop while US businessmen looked on aghast.
A separate article quoted experts as calling Trump's behaviour "diplomatically inept".
Trump has already infuriated Beijing by questioning longstanding US policy on Taiwan, calling Beijing a currency manipulator and threatening punitive tariffs on Chinese imports.
"Trump is not behaving as a president who will become master of the White House in a month. He bears no sense of how to lead a superpower," the often nationalistic Global Times, which has close ties to the ruling Communist Party, said in an editorial.
There are broader tensions in the South China Sea, where China has moved to fortify its claims to the region by expanding tiny reefs and islets into artificial islands hosting military facilities.
Brunei, Malaysia, the Philippines, Vietnam and Taiwan have competing claims in the waterway.
Its military has conducted several operations in which ships and planes have passed close to the sites Beijing claims.
"No matter how powerful the US Navy is, it cannot act on the bottom line of China's security," said a second editorial about the probe seizure in the Global Times Monday.
"If we see sonar and underwater gliders deployed by foreign ships in the South China Sea in the future, we would rather mistakenly capture a thousand than miss a single one."