Rejecting the Chinese claim of air intrusion, India on December 7 said that the drone was on a training mission and lost control and crossed over the Line of Actual Control in the Sikkim Sector. China on Thursday had expressed “strong dissatisfaction” over the intrusion of its airspace.

“The Indian UAV intruded into China's airspace and crashed recently, and China's border troops have conducted identification and verification over the vehicle,” said Zhang Shuili, deputy head of the combat bureau of the Western Theater Command's joint staff department, in a statement on Thursday.

"India's move has infringed upon China's territorial sovereignty, and we are strongly dissatisfied with and opposed to this," he said.

"We will fulfill our mission and responsibility and defend China's national sovereignty and security resolutely,” he added.

Although the Chinese did not disclose the location of the accident but New Delhi, in its statement, informed that the incidence took place across the border in the Sikkim sector.

“An Indian UAV which was on a regular training mission inside the Indian territory lost contact with the ground control due to some technical problem and crossed over the LAC in the Sikkim Sector,” said Ministry of Defence in a statement.

According to India, the “border security personnel immediately alerted their Chinese counterparts to locate the UAV” and the Chinese “reverted with the location details of the UAV.”

India has launched an investigation to find out the cause of the incident.

“The matter is being dealt in accordance with the established protocols through institutional mechanisms to deal with situations along the India-China border areas,” Indian statement added.

This incidence can refuel the border tension that has cooled off post the peaceful pullback from 72 days standoff at the Doklam plateau.

Incidentally, the Chinese Foreign Minister Wang Yi and Russian Foreign Minister Sergey Lavrov will attend the 15th China-Russia-India Foreign Ministers' Meeting hosted by Indian Foreign Minister Sushma Swaraj in New Delhi on December 11.