India has cautioned China against making “exaggerated and untenable claims” on the sovereignty of the Galwan Valley even as both nations tried to calm tensions in the Himalayan region where their soldiers engaged in a deadly clash.

Twenty Indian troops were killed in the clash on Monday night (local time) that was the deadliest conflict between the sides in 45 years.

China has not disclosed whether its forces suffered casualties.

In a sharp rebuke to the Chinese foreign ministry claiming the valley, India’s External Affairs Ministry spokesman Anurag Srivastava said that, while both sides agreed to handle the situation responsibly, “making exaggerated and untenable claims is contrary to this understanding”.

Both sides have accused each other of instigating the clash between their forces in the valley, part of the disputed Ladakh region along the Himalayan frontier.

Media reports said senior army officers of the two sides met on Wednesday to defuse the situation, but there was no confirmation from either side.

Indian security forces said neither side fired any shots, instead throwing rocks and trading blows. The Indian soldiers, including a colonel, died of severe injuries and exposure in the area’s sub-zero temperatures, officials said.

It is understood that many of the soldiers either fell or were pushed into a river.

The clash escalated a stand-off in the disputed region that began in early May, when Indian officials said Chinese soldiers crossed the boundary at three different points, erecting tents and guard posts and ignoring warnings to leave.

That triggered shouting matches, stone-throwing and fistfights, much of it replayed on television news channels and social media.

Chinese Foreign Minister Wang Yi warned New Delhi not to underestimate Beijing’s determination to safeguard what it considers its sovereign territory.

His comments came in a phone call on Wednesday with his Indian counterpart, Subrahmanyam Jaishankar.

Wang said China demanded that India conduct a thorough investigation and “harshly punish” those responsible.

“The Indian side would best not make an incorrect judgement of the situation”, Mr Wang said in a statement issued by the foreign ministry.

He said Indian forces had crossed the Line of Actual Control that divides thousands of troops from both sides deployed in the area.

Jaishankar, in turn, accused China of erecting a structure in the Galwan Valley, which he called a “premeditated and planned action that was directly responsible for the resulting violence and casualties,” according to a statement.

But he added that both sides were committed to further disengaging on the remote plateau of the Himalayan terrain.

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Indian Prime Minister Narendra Modi hailed the soldiers killed in the clashes.

“Their sacrifices won’t go to waste,” he said.

“For us, the unity and sovereignty of the country is the most important thing. India wants peace, but when provoked, it is capable of giving a fitting reply, be it any kind of situation.”

The clash has provoked fierce protests in India, with people burning Chinese flags.

Indians burn an effigy of Chinese President Xi Jinping during a protest against the Chinese government in Lucknow, India. Photo: AP

China claims about 90,000 square kilometers of territory in India’s northeast, while India says China occupies 38,000 square kilometers of its territory in the Aksai Chin Plateau in the Himalayas.

The Line of Actual Control is the border established following a war between India and China in 1962 that resulted in an uneasy truce.

-with agencies