India and China accused each other on Tuesday of firing warning shots during a confrontation the day before at their disputed border in a marked escalation of tensions between the two nuclear-armed neighbors.
It was the first time in decades that both sides said shots were fired at the frontier, where long-standing, mutual protocols forbid the use of firearms.
Such protocols did not prevent the two countries from engaging in their deadliest violence in more than 50 years in June, when soldiers armed with clubs studded with nails and metal rods clashed in a remote area of the western Himalayas.
Twenty Indian soldiers were killed. The number of Chinese casualties remains unknown.
Both countries moved thousands of troops as well as tanks, artillery and fighter jets to areas close to the disputed and unmarked border, which is known as the Line of Actual Control.