China expressed "strong dissatisfaction" with India Thursday over the recent crash of an Indian drone in Chinese territory, an incident that could cause more friction along their disputed border.
Indian and Chinese troops confronted each other between June and August this year - at one stage even resorting to scuffling and throwing stones - on a remote plateau near the borders of India, its ally Bhutan, and China, in the most serious and prolonged standoff in decades.
The nuclear-armed Asian giants have tried to develop their ties in recent years but there is still deep distrust over their disputed border, which triggered war in 1962.
China's defense ministry said in a statement the Indian drone had crashed in "recent days" but it did not give a location.
"This action by India violated China's territorial sovereignty. We express strong dissatisfaction and opposition," Zhang Shuili, a military official in China's western battle zone command, was quoted as saying in a ministry statement.
"China's border defense forces took a professional and responsible attitude in conducting an inspection of the device," Zhang said, adding that the military would "resolutely defend" China's sovereignty and security.
The Indian army said an unmanned aerial vehicle was on a training mission over Indian territory when it developed technical problems and crossed a so-called line of actual control separating the countries' militaries.
Indian border guards alerted their Chinese counterparts about the drone soon afterwards, an Indian army spokesman said.
After the weeks of confrontation on the wind-swept Doklam plateau this year, the two sides agreed to an "expeditious disengagement" of troops about a week before Chinese President Xi Jinping and Indian Prime Minister Narendra Modi met in an effort to mend ties at a summit in China in September. But the mountainous border remains sensitive for both sides.
In November, China criticized a visit by Indian President Ram Nath Kovind to the remote state of Arunachal Pradesh, which China claims, saying China opposed any activities by Indian leaders in disputed areas.