NEW DELHI — Tensions along the India-China border took an alarming turn on Tuesday after Chinese and Indian officials accused each other’s soldiers of firing warning shots, apparently the first time in decades that guns had been aggressively used along the disputed frontier.
Military activities along the unofficial border, which zigs and zags through some of the highest mountain ranges on Earth, are difficult to verify.

But according to a statement from the Chinese military, Indian troops on Monday “took the outrageous step of firing warning shots” near a Chinese border patrol. India’s actions, the Chinese said, were “a grave military provocation of a vile character.”

Indian officials, however, denied their soldiers had fired any shots and said it was the Chinese who broke the long tradition of refraining from using firearms, a protocol in place for decades.
Chinese soldiers “fired a few rounds in the air in an attempt to intimidate” Indian troops, the Indian military said in a statement. “Despite the grave provocation,” the statement said, Indian troops “exercised great restraint and behaved in a mature and responsible manner.”