The move followed the creation of a similar demilitarised zone last year some 150km away along the Galwan river, where 20 Indian soldiers and at least four Chinese troops were killed in brutal hand-to-hand combat. That escalation on June 15, the first time casualties were reported along the disputed frontier since 1975. China only acknowledged the deaths on February 19.

While the pullback has calmed tensions for the moment, some members of India’s security establishment believe the creation of non-militarised areas work in Beijing’s favour, according to the officials, who asked not to be identified discussing private conversations. They said China raised suspicions by objecting to an Indian proposal for both countries to patrol the area around the lake on alternate days on the grounds that it would affect Beijing’s sovereignty.

Indian defence and security officials had raised their concerns about the area around Pangong Tso with the government but it opted for a speedy disengagement. On February 10 the two countries began rolling back soldiers, tanks and artillery guns that were stationed around the lake in rifle range of each other for nearly 10 months.

The Indian army, Defence Ministry and the Prime Minister’s Office did not immediately reply to requests for comment.

China’s Foreign Ministry said the creation of non-militarised zones along the border was “made up by the media” in response to questions. On Friday in Beijing, Foreign Ministry spokesman Wang Wenbin said the situation on the ground “significantly eased” after the disengagement.

“The two sides should cherish this hard won momentum and consolidate existing outcomes, maintain momentum for consultation and further ease the situation,” he said at a regular briefing.

Distrust between the two militaries could lead to further misunderstandings, according to Sushant Singh senior fellow at the New Delhi-based Centre for Policy Research and author of Mission Overseas: Daring Operations by Indian Military.

“The model of buffer zones is temporary and full of challenges,” he said. “More importantly, India’s options are limited in case China – a much bigger military power – violates the agreement.”

If the demilitarised areas end up keeping the peace, they could become a model for how India and China deal with a border nearly as long as the one between the US and Mexico.

Nationalism stoked by the fighting has had an economic impact, with Modi’s government banning hundreds of Chinese apps, slowing approvals for Chinese investment and strengthening security ties with the US, Japan and Australia.

Still, while the demilitarised zones are aimed at preventing clashes of the sort that erupted last summer, the competing claims between the two sides remain, officials said. And a previous experiment with creating a demilitarised zone on the border with China has shown that it is not a guarantee of peace.

An 80 sq km patch of pasture land along the southern edge of the Tibetan Plateau and the Indian border state of Uttarakhand was the first to be set aside as no-man’s-land in the 1950s. Yet that has failed to prevent conflict in the area, according to Jayadeva Ranade, a member of India’s National Security Council Advisory Board and head of the New Delhi-based Centre for China Analysis and Strategy.

“Uttarakhand border continues to be a hotspot,” he said. “Beijing’s track record of respecting agreements is poor.”