NEW DELHI (AFP) - The tiny Himalayan kingdom of Bhutan has protested to its mighty neighbour China over road building in disputed territory that set off new frictions between Beijing and the Indian government on Thursday (June 29).

China made a new demand on Thursday that Indian troops return to their side of the border between India's Sikkim state and Tibet on the Chinese side.

Highlighting the widening tensions over the remote mountain zone, Bhutan's ambassador to New Delhi, Vetsop Namgyel, said his government had called on China's People's Liberation Army to stop building the road near where the Bhutan, Indian and Chinese borders meet.

"We have issued a demarche to China through its diplomatic mission here," Namgyel told the Press Trust of India (PTI) news agency.

He said the road was "in violation of an agreement between the two countries." Bhutan, which has a population of less than 800,000, and China do not have formal relations but maintain contacts through their missions in New Delhi.

"Doklam is a disputed territory and Bhutan has a written agreement with China that pending the final resolution of the boundary issue, peace and tranquility should be maintained," the ambassador said.

There is a dispute over the sovereignty of the district, which China calls Donglang. The showdown is, however, part of a wider dispute between India and China over the 4,057 kilometer (2,520 mile) border through mountain passes.

India's army chief, General Bipin Rawat, travelled to Sikkim on Thursday, just days after Beijing accused Indian border guards of crossing into its territory to stop the construction of the road.

Border 'scuffle'

Indian media reports said there had been a "scuffle" between Indian and Chinese troops after PLA soldiers damaged two old Indian bunkers.

China has since stopped pilgrims crossing into Tibet to visit a mountain revered as the home of the Hindu god Shiva because of the showdown, the reports added. The Indian government has not commented on the tensions.

India and China have long disputed parts of their frontier in the Himalayas.

In 1962 there was a brief war over the Indian state of Arunachal Pradesh. In 2014, Chinese troops moved into Sikkim territory claimed by India sparking a two week standoff.

Sikkim is the least populous and second smallest of India's states, but its location gives it strategic importance.

While India has remained silent over the dispute, China has angrily reinforced its claim that it has every right to build the road despite Bhutan's protests.

Lu Kang, a Chinese foreign ministry spokesman, made a new demand on Thursday that Indian troops withdraw from Chinese territory. India has not acknowledged that its soldiers are across the border.

"The reality is that the Indian troops illegally trespassed into the territory" of China, Lu told a Beijing briefing.

"Truth cannot be covered up, and we again urge the Indian side to abide by the historical boundary convention, respect Chinese territorial sovereignty and withdraw the troops back to the Indian side of the boundary to avoid any escalations." Lu said China would release photos of Indian soldiers in Chinese territory.

China says the Sikkim-Tibet border was decided under a 1890 accord with Britain.