BEIJING:  China's defence ministry on Monday warned India not to harbour any illusions about the Chinese military's ability to defend its territory, amid a festering border dispute.

The stand-off on a plateau next to the mountainous Indian state of Sikkim, which borders China, has ratcheted up tension between the neighbours, who share a 3,500-km (2,175-mile) frontier, large parts of which are disputed.

"Shaking a mountain is easy but shaking the People's Liberation Army is hard," ministry spokesman Wu Qian told a briefing, adding that its ability to defend China's territory and sovereignty had "constantly strengthened".

Early in June, according to the Chinese interpretation of events, Indian guards crossed into China's Donglang region and obstructed work on a road on the plateau.

The two sides' troops then confronted each other close to a valley controlled by China that separates India from its close ally, Bhutan, and gives China access to the so-called Chicken's Neck, a thin strip of land connecting India and its remote northeastern regions.

India has said it warned China that construction of the road near their common border would have serious security implications.

The withdrawal of Indian border guards was a precondition for resolving the situation, Wu reiterated.

"India should not leave things to luck and not harbour any unrealistic illusions," Wu said, adding that the military had taken emergency measures in the region and would continue to increase focused deployments and drills.

"We strongly urge India to take practical steps to correct its mistake, cease provocations, and meet China halfway in jointly safeguarding the border region's peace and tranquillity," he said.

Indian officials say about 300 soldiers from either side are facing each other about 150 metres (yards) apart on the plateau.

They have told Reuters that both sides' diplomats have quietly engaged to try to ensure the stand-off does not escalate, and that India's ambassador to Beijing is leading the effort to find a way for both sides to back down from confrontation without losing face.

Chinese state media have warned India of a fate worse than the defeat it suffered in their brief border war in 1962.

This month, state media said China's military had carried out live fire drills close to the disputed area.