Both sides agreed in the call between China's Wang Yi and India's Subrahmanyam Jaishankar to "deal fairly" with the events in the Galwan Valley and maintain peace in border areas, China's foreign ministry said.

The "hand-to-hand" fighting in the disputed Himalayan region left 20 Indian soldiers dead, according to India's military, with both sides blaming the other for the violence.

It is the first deadly clash between the nuclear powers in decades. China has refused to confirm if it suffered any casualties.

The Chinese foreign ministry statement said that both sides agreed to "cool down the situation on the ground as soon as possible, and maintain peace and tranquility in the border areas in accordance with the agreement reached so far between both countries."

Wang demanded that "India conduct a thorough investigation" on the situation, punish those responsible and immediately stop all provocations to ensure such an incident does not occur again, the statement said.

"The Indian side must not misjudge the current situation, and must not underestimate China's firm will to safeguard its territorial sovereignty," it added.

According to Beijing, Jaishankar said India is willing to peacefully resolve disputes in the border areas through dialogue and ease tensions there.