NEW DELHI/SRINAGAR: A Himalayan border standoff between old foes India and China was triggered by India’s construction of roads and air strips in the region as it competes with China's spreading Belt and Road initiative, Indian observers said on Tuesday.

Soldiers from both sides have been camped out in the Galwan Valley in the high-altitude Ladakh region, accusing each other of trespassing over the disputed border, the trigger of a brief but bloody war in 1962.

About 80 to 100 tents have sprung up on the Chinese side and about 60 on the Indian side where soldiers are billeted, Indian officials briefed on the matter in New Delhi and in Ladakh's capital, Leh, said.

Both were digging defences and Chinese trucks have been moving equipment into the area, the officials said, raising concerns of a long faceoff.

"China is committed to safeguarding the security of its national territorial sovereignty, as well as safeguarding peace and stability in the China-India border areas," the Chinese Foreign Ministry spokesperson's office said in a statement.

"At present, the overall situation in the border areas is stable and controllable. There are sound mechanisms and channels of communication for border-related affairs, and the two sides are capable of properly resolving relevant issues through dialogue and consultation.”

There was no immediate Indian foreign ministry comment. It said last week Chinese troops had hindered regular Indian patrols along the Line of Actual Control (LAC).

But interviews with former Indian military officials and diplomats suggest the trigger for the flare-up is India’s construction of roads and air strips.

"Today, with our infrastructure reach slowly extending into areas along the LAC, the Chinese threat perception is raised," said former Indian foreign secretary Nirupama Rao.

"Xi Jinping’s China is the proponent of a hard line on all matters of territory, sovereignty. India is no less when it comes to these matters either," she said.

After years of neglect Prime Minister Narendra Modi’s government has pushed for improving connectivity and by 2022, 66 key roads along the Chinese border will have been built.

One of these roads is near the Galwan valley that connects to Daulat Beg Oldi air base, which was inaugurated last October.

"The road is very important because it runs parallel to the LAC and is linked at various points with the major supply bases inland," said Shyam Saran, another former Indian foreign secretary.

"It remains within our side of the LAC. It is construction along this new alignment which appears to have been challenged by the Chinese."

China's Belt and Road is a string of ports, railways, roads and bridges connecting China to Europe via central and southern Asia and involving Pakistan, China's close ally and India's long-time foe.