China expressed "strong dissatisfaction" with India on Thursday after the recent crash of an Indian drone in what the Chinese military said was Chinese territory, an incident that could cause further friction along the two countries' disputed border.
"This action by India violated China's territorial sovereignty. We express strong dissatisfaction and opposition," said Zhang Shuili, a senior military official in China's western battle zone command, according to a Defence Ministry statement.
"China's border defence forces took a professional and responsible attitude in conducting an inspection of the device," Zhang said, adding that the military would resolutely defend national sovereignty and security.
It said only that the drone crashed in "recent days" and did not give a location.
China and India have tried to develop two-way ties in recent years but there is still deep distrust over the border dispute.
In June, July and August, Indian and Chinese troops had been confronting each other at the Doklam plateau near the borders of India, its ally Bhutan and China in the most serious and prolonged standoff in decades.
The two sides agreed to an "expeditious disengagement" of troops there about a week before Chinese President Xi Jinping and Indian Prime Minister Narendra Modi met in an effort to mend ties at a summit hosted by China in September.
In November, China criticised a visit by Indian President Ram Nath Kovind to Arunachal Pradesh, which China claims, saying China opposed any activities by Indian leaders in disputed areas.