The incident occurred during a “de-escalation process” underway in the Galwan Valley, where a large troop build up has reportedly been taking place for weeks.
The Indian army says 20 soldiers have been killed in a clash with Chinese troops on a disputed Himalayan border.
The army originally reported three Indian soldiers had died, but later on Tuesday said 17 additional soldiers succumbed to injuries they suffered in the sub-zero temperatures of the high-altitude terrain.
The incident occurred during a "de-escalation process" underway in the Galwan Valley in the disputed Aksai Chin-Ladakh area, where a large troop build-up has reportedly been taking place for weeks now on both sides of the border, before senior military commanders began talks earlier this month.
According to the Indian army statement, there was loss of life "on both sides".
The statement did not specify the number of additional Chinese casualties. It added that senior military officials from both sides are currently meeting to defuse the situation.
China has accused Indian forces of carrying out "provocative attacks" on its troops and has not said if any of its soldiers died.
Thousands of soldiers on both sides have been facing off for more than a month.
The clash – during which neither side fired any shots, according to Indian officials – is the first deadly confrontation between the two Asian giants since 1975.
EXPLAINED: What's behind China and India's long-running Himalayas dispute?
At a regular press conference Tuesday, Chinese Foreign Ministry spokesman Zhao Lijian said that on Monday "Indian troops seriously violated our consensus and twice crossed the border line for illegal activities and provoked and attacked Chinese personnel which lead to serious physical conflict between the two sides."
"China has lodged strong protest and representation with the India side, and we once again we solemnly ask the India side to follow our consensus and strictly regulate its front line troops and do not cross the line and do not stir up troubles or take unilateral moves that may complicate matters," Zhao added.
"We both agreed to resolve this issue through dialogue and consolation and make efforts for easing the situation and upholding peace and tranquility in the border area."
Monday's loss of life would be the first time there have been any casualties along the disputed border for over four decades, said Happymon Jacob, an associate professor and political analyst at Delhi's Delhi's Jawaharlal Nehru University.
"We have not had casualties on the LAC for at least 45 years," he said.
"This is perhaps a gamechanger. This is perhaps the beginning of the end of the rapport that India has enjoyed with China for 45 years."
Tensions have been growing in the Himalayas along one of the world's longest land borders since last month, with New Delhi and Beijing both accusing the other of overstepping the Line of Actual Control (LAC) that separates the two nuclear armed neighbours.
The territory has long been disputed, erupting into numerous minor conflicts and diplomatic spats since a bloody war between the two countries in 1962.
The Line of Actual Control runs between Chinese-controlled Aksai Chin and the rest of the disputed Jammu and Kashmir region.
The rough border line was the result of the India China border dispute in 1962, but neither side agrees exactly where it is or how long it is.
Aksai Chin is administered by China as part of Xinjiang, but is also claimed by the Indian government as part of Ladakh.
The reported troop build up had left many worried about the potential for a confrontation, particularly as both Chinese and Indian media have published jingoistic calls for action.
Both Chinese President Xi Jinping and Indian Prime Minister Narendra Modi have built public support in large part on nationalism and a promise of future greatness. This often translates into aggressive rhetoric, particularly when playing to a domestic audience.
Such an approach was evidenced in Chinese coverage of the PLA maneuvers in the Himalayas.
Equally, despite Delhi's public calls for easing tensions, leading Indian government figures have struck an aggressive tone, with Home Affairs Minister Amit Shah telling a rally of the ruling Bharatiya Janata Party (BJP) earlier this month that "any intrusion into the the borders of India will be punished."
"Some used to say that US and Israel were the only countries which were willing and capable of avenging every drop of the blood of their soldiers," Shah said. "(Modi) has added India to that list.''
Writing for CNN this month, retired Indian general Bikram Singh said that part of the problem is that the de facto border, the LAC, is so ill-defined.
"At strategic and operational levels, both militaries have exercised restraint," he said.
"However, at the tactical level, face-offs occur due to differing perceptions of where the actual border is as the LAC is not delineated on the ground. While face-offs get resolved locally, those related to the building of infrastructure, such as roads and defence fortifications, invariably take longer and require a combination of military and diplomatic initiatives."
Speaking before the most recent clash, former Indian Foreign Secretary Nirupama Rao said she hoped the current crisis won't lead to an abandonment of long-standing diplomatic negotiations over the disputed territory.
"Even if tensions rise and tempers fray, they would do well to remember that they have to continue to manage their differences in a grown-up way because armed clashes and military combat can have extremely serious repercussions for the stability of the region going beyond the ambit of the purely bilateral relationship between the two countries," she said.
– Reported with AAP and CNN
Source: 9News https://www.9news.com.au/world/indian-soldiers-killed-chinese-troops-country-border-himalayas-tensions-asia-news/dbccdc55-abb5-4835-8da9-a24bc1d5d321