Satellite images from the Galwan Valley in eastern Ladakh show how the clash between India and China erupted after days of build-up.
The clash took place at a point called PP-14 or Patrolling Point 14 a few km from the Line of Actual Control (LAC), the de-facto border between India and China.
New satellite images from Reuters taken on Tuesday show a massive build-up on the Chinese side of the LAC.
Troops from this area likely surged to India's areas in the Galwan Valley, where hundreds of soldiers clashed on Monday at a height of 15,000 feet up in the Himalayas. Indian soldiers were assaulted with iron rods, stones wrapped in barbed wire and nail-studded clubs in the fight that started in the afternoon and went on till midnight.
Soldiers were even thrown off a high ridge into the icy Galwan river.
Indian soldiers observed Chinese ambulances taking away bodies and casualties in the area. Helicopters took them away to other locations.
The area also saw violent clashes in 1962, when Indian posts were overrun. But in over five decades, there had been no violence and no active Chinese presence.
It is believed that the Chinese were looking to target India's new road, which links Daulat Beg Oldie to the North with Darbuk to the South.
Twenty soldiers including a Colonel were killed in the line of duty on Monday. Their sacrifice will not be in vain, Prime Minister Narendra Modi said in his first comments on the Ladakh clash, warning that India "is capable of giving a fitting reply if provoked".
About 45 Chinese soldiers were also killed or injured, said army sources.