According to the Indian army, three Indian soldiers have been killed in a violent incident involving Chinese soldiers.
The incident took place on Monday evening in the controversial Ladakh border region in the Himalayas.
Senior military officials from the two neighbouring countries would meet on Tuesday to avoid escalation of the situation.
Tensions between the two nuclear powers have increased recently. Recent injuries between troops on both sides have already resulted in several injuries.
China and India waged a brief war in 1962 over their Himalayan border, which China won. There have been several incidents since then.
The course of the boundary is still not clear. US President Donald Trump recently offered to mediate in the conflict, which neighbouring countries rejected.
The Chinese Foreign Ministry spokesman said on Tuesday that he was unaware of any incident on the border with India.