Brawls and face-offs flare up on a fairly regular basis between the two nuclear-armed giants over their 3,500-kilometre frontier, which has never been properly demarcated, but no one has been killed in decades.
At least 20 Indian soldiers have been killed in a violent face-off with Chinese forces on the disputed Himalayan border, the Indian army said late Tuesday, the deadliest clash between the nuclear-armed neighbours in decades.
India had earlier said three of its troops were killed, but in a statement later Tuesday the army added that 17 more "who were critically injured (on Monday) in the line of duty at the stand-off location and exposed to sub-zero temperatures in the high altitude terrain have succumbed to their injuries, taking the total that were killed in action to 20."
The fighting comes amid accusations that India has effectively ceded to some of the disputed territory to China.
Brawls and face-offs flare on a fairly regular basis between the two nuclear-armed giants over their 3,500-kilometre frontier, which has never been properly demarcated, but no one has been killed in decades.
Earlier, the Indian army said that there were "casualties on both sides."
"A violent face-off took place yesterday (Monday) night with casualties on both sides. The loss of lives on the Indian side includes an officer and two soldiers," an Indian army spokesman said in a statement.
"Senior military officials of the two sides are currently meeting at the venue to defuse the situation."
Editor-in-chief of China's Global Times newspaper echoed the sentiments.
"Based on what I know, Chinese side also suffered casualties in the Galwan Valley physical clash," Hu Xijin said in a tweet.
He did not give further details.
An Indian army officer based in the region said that there had been no shooting, and that the officer killed had been a colonel.
"There was no firing. No firearms were used. It was violent hand-to-hand scuffles," the officer said on condition of anonymity.
'Provocation and attack'
Beijing on Tuesday confirmed the incident and accused India of crossing the border and "attacking Chinese personnel."
Chinese Foreign Ministry spokesman Zhao Lijian said Indian troops "crossed the border line twice ... provoking and attacking Chinese personnel, resulting in serious physical confrontation between border forces on the two sides."
The Indian army said the incident took place in the Galwan Valley in the high-altitude Ladakh region – which is just opposite Tibet.
Thousands of troops from the two nuclear-armed neighbours have been involved in the latest face-off since May.
On May 9, several Indian and Chinese soldiers were injured in a clash involving fists and stone-throwing.
The Chinese Foreign Ministry said only last week that a "positive consensus" on resolving the latest border issue was achieved following "effective communication" through diplomatic and military channels.
In a later statement, India's Foreign Ministry had said the two sides would "continue the military and diplomatic engagements to resolve the situation and to ensure peace and tranquility in the border areas."
But sources and Indian news reports suggested that India appeared to have effectively ceded to China areas that the People's Liberation Army occupied in recent weeks, notably parts of the northern side of the Pangong Tso lake and some of the strategically important Galwan river valley.
India's Prime Minister Narendra Modi and Chinese leader Xi Jinping have sought to ease tensions at summits over the past two years when they agreed to boost border communications between their militaries.