China's foreign and defence ministries have accused Indian border guards of crossing into its territory, provoking tensions along the Line of Actual Control (LAC) in the state of Sikkim, which is located in northeastern India and shares a border with Tibet.
The Indian troops reportedly crossed the border and obstructed work on a road on the other side, according to Reuters.
"China is dedicated to developing bilateral relations, and will staunchly defend its legitimate rights," the ministry said on Tuesday (27 June). "China hopes India will meet it halfway, not do anything to complicate the border issues and jointly maintain the good momentum of relations."
China's foreign ministry demanded that India immediately withdraw its border forces. It has also ordered a thorough investigation of this matter, according to a statement from the ministry spokesman late on Monday.
The foreign ministry said the Indian border guards had "obstructed normal activities" of the Chinese frontier troops in the Donglang area recently and that the Chinese side had to take counter-measures.
It is unclear when the alleged border incursion happened, but in view of this event, Beijing said it has suspended a mountain pass in the Himalayas, known as Nathu La, which allows Indian pilgrims to enter China.
The pass, which sits 4,545 meters above the sea level, connects the Indian state of Sikkim with China's Tibet Autonomous Region, shortening the travel distance to important Hindu and Buddhist pilgrimage sites in the region. Those sites were at the centre of fierce border skirmishes between India and China in 1967.
In 2015, China agreed at Indian Prime Minister Narendra Modi's request to let Indians access the mountain. However, the famous route has been blocked for the past one week, Indian media reports suggest.
India's foreign or defence ministry is yet to comment on the border incursion accusation.
India media reports also suggest that the tensions between the frontier troops from both the sides have been ongoing for the past weeks, resulting in a tense face-off. Chinese troops reportedly crossed into Sikkim and destroyed two make-shift Indian army bunkers earlier this month, Press Trust of India news agency cited its unnamed sources as saying.
Delhi-based NDTV broadcaster reported that India pilgrims were made to wait for nearly a week at the border after China blocked the Nathu La pass.
Relations between India and China have long been rocky as a result of territorial disputes and the 1962 border war.
Small incursions along the LAC, the 4,000km de facto border across the Himalayas, are reported to be common, with both the sides holding more than a dozen rounds of bolder talks since 1990s. However, little progress has been made to resolve the dispute.
When Chinese President Xi Jinping met Modi earlier this month, he urged the Indian leader that both the countries should work to "appropriately" manage their differences.
Recently, Beijing strongly objected to Delhi allowing the Dalai Lama to tour sensitive northeastern Indian border state Arunachal Pradesh. Chinese state-media too had lashed out at India over the Buddhist monk's visit, saying Delhi would pay "dearly" for escalating tensions with Beijing over its territorial dispute.