China on Wednesday virtually accused India of having a "hidden agenda" as it indicated that Indian troops had stopped PLA soldiers from building a road in Donglang, a region at the centre of a long-standing dispute with Bhutan.
The remarks by foreign ministry spokesperson Lu Kang at a news briefing added another twist to the standoff between Indian and Chinese troops along the frontier in Sikkim.
Donglang, or Doklam, is under Chinese control and lies within the Tibet Autonomous Region (TAR) but is claimed by Bhutan. Donglang is located at the narrow and strategic tri-junction of India, China and Bhutan, a short distance from Nathu La pass.
The Chinese foreign ministry indicated the latest incident amounted to Indian soldiers trespassing into its territory.
"The Donglang area (site of the standoff) has belonged to China since ancient times and does not belong to Bhutan," Lu told the news briefing while reacting to a report in Hindustan Times which said Bhutan could be key to the military stand-off at Nathu La.
Without naming India, Lu said if a third party tried to interfere in the matter "out of a hidden agenda", it was disrespectful to Bhutan. Lu said it was up to India to judge whether it had interfered in Bhutan's internal affairs.
"If India wants to raise the (Donglang dispute) I should say it doesn't belong to Bhutan or to India," he said, adding "no country" had the right to interfere in China's efforts to build roads in the area.
"Though the China-Bhutan border has not been delimited, no third party should interfere in this matter and make irresponsible remarks or action," Lu added.
India and Bhutan have close relations, especially in foreign policy and security, while Thimpu and Beijing are yet to establish a diplomatic relationship.
The sequence of events leading to the military standoff at Nathu La had not added up till China accused India of trespassing into its territory at Donglang.
A PTI report from New Delhi had said on Monday that Indian and Chinese troops scuffled near Doka La area in the first week of June before soldiers from the People's Liberation Army (PLA) damaged bunkers on the Indian side.
China denied the allegations and the defence ministry said late on Monday night that Indian troops "crossed the border with China in an attempt to block a road construction in Donglang".
In India, the focus had been on the face-off between the two armies at Nathu La, the suspension of the Kailash Mansarovar Yatra and the harassment of Indian pilgrims.
Donglang is part of the border dispute between China and Bhutan that has remained unresolved despite 24 rounds of negotiations.
There is not much of a dispute between India and China in Sikkim despite the unmarked border stretching 3,488 km.
"After we recognised Sikkim as one part of India (in 2003), the two governments made sure that there were no problems. Not like the other parts of the border," said Hu Shisheng, director of the Institute of South and Southeast Asia and Oceania Studies at the China Institutes of Contemporary International Relations.
Hu speculated it was possible that Bhutan had asked for India's help in patrolling the area. "So, one thing is that Bhutan asking India to take the responsibility to patrolling on the border. We know that Bhutan is under the protection of India," he added.