An Indian army officer and two soldiers were killed in Ladakh, the army said. (Representational)
After an Indian army officer and two soldiers were killed at the Galwan Valley in Ladakh, China "calls on India to not take unilateral actions or stir up trouble", reported news agency Reuters.
The comment was made by China's Foreign Ministry.
The army in a statement a short while ago said the Indian army personnel were killed in "a violent face-off" last night and that military representatives of both countries are meeting now at the location to defuse tensions. The statement spoke of "casualties on both sides."
Beijing accused Indian troops of crossing into its territory.
Army sources said the three Indian personnel killed were not shot, suggesting that they may have been killed in hand-to-hand combat.
Foreign Ministry spokesman Zhao Lijian told reporters in Beijing Indian troops crossed the border twice on Monday, "provoking and attacking Chinese personnel, resulting in serious physical confrontation between border forces on the two sides". Beijing has lodged "strong protests and solemn representations" to Delhi, he said.
"We again solemnly request that India follows the relevant attitude and restrains its frontline troops," he said. "Do not cross the border, do not provoke trouble, do not take any unilateral action that would complicate the border situation."
Tensions flare on a fairly regular basis between India and China over their 3,500-kilometre (2,200-mile) border.
Last week, China said it had reached a "positive consensus" with India over resolving tensions that had built up in recent weeks over at least five different places on the border in Ladakh and Sikkim.
Prime Minister Narendra Modi and Chinese leader Xi Jinping have sought to improve relations at summits over the past two years.
The huge escalation of hostilities comes after high-level talks between military officers of both sides. There were reports last week that both armies had thinned out forces; however, experts warned that soldiers, tanks and other armoured carriers remained heavily deployed in the high-altitude region. Indian sources have also said that China has advanced into new territory at the strategically vital Pangong Lake.