This is seen as the first deadly violence since the two nuclear armed neighbours faced off in a border dispute 45 year ago.
The Indian and Chinese troops fought each other with fists and rocks along the high-altitude Himalaya terrain in a clash that left 20 Indian soldiers dead, Indian authorities said Tuesday, reports AP.
China accused Indian forces of carrying out "provocative attacks" on its troops and has not said if any of its soldiers have died.
The Indian army said in its statement that the two sides had "disengaged" from the disputed Galwan area where they clashed overnight on Monday.
The army originally reported that three Indian soldiers had died, but later said 17 additional soldiers succumbed to injuries they suffered in the sub-zero temperatures where the clash occurred in the Himalayan region of Ladakh.
Thousands of soldiers on both sides have been facing off for over a month along a remote stretch of the 2,100-mile Line of Actual Control, the border established following a war between India and China in 1962 that resulted in an uneasy truce.
The clash Monday — during which neither side fired any shots, according to Indian officials — is the first deadly confrontation between the two Asian giants since 1975.
Vivek Katju, a retired Indian diplomat, said the deadly violence represented a dramatic departure from the four-decades-old status quo of troops from the two countries facing off without any fatalities.
"The political class and the security class as a whole will have to do very serious thinking about the road ahead," he said.
The Indian army said in a statement earlier Tuesday that a "violent faceoff" took place in Ladakh's Galwan Valley on Monday night, "with casualties on both sides."
Foreign Ministry spokesman Zhao Lijian gave no details of any casualties on the Chinese side, but said that China had strongly protested the incident while still being committed to maintaining "peace and tranquility" along the disputed and heavily militarized border.
"But what is shocking is that on June 15, the Indian troops seriously violated the consensus of the two sides, crossed the border illegally twice and carried out provocative attacks on Chinese personnel, resulting in serious physical conflicts between the two border forces," Zhao said.
India's Ministry of External Affairs said in a statement that the incident happened "as a result of an attempt by the Chinese side to unilaterally change the status quo" in the Galwan Valley.