Indian and Chinese troops appeared to exchange warning shots along their disputed border in Ladakh on Monday, the first time firearms have been used by soldiers from the neighbouring superpowers since 1975.
While no casualties were reported, the clash is likely to further heighten tensions after the two sides were engaged in fatal hand-to-hand combat earlier this year.
China claimed on Tuesday that Indian soldiers had opened fire to ward off a unit patrolling in a contested mountainous region.
But India, officially, denied they fired shots, countering that China had used their guns to intimidate Indian forces.
However, Indian Army sources told The Telegraph a Chinese patrol had advanced towards Indian territory on strategically important mountain tops near Pangong Tso Lake. They claimed Indian units fired warning shots in the air.
Zhao Lijian, a Chinese Ministry of Foreign Affairs spokesperson, said: “It is the first time since 1975 that peace on the border of the two countries was broken by gunshots.”
In a statement released on Tuesday, the Indian Government condemned the PLA for “blatantly violating agreements and carrying out aggressive maneuvers” and reiterated its commitment to “protect national integrity and sovereignty at all costs.”
Years of fragile peace has set a convention that states the two sides do not use guns to avoid escalations of violence in remote terrain.
Because the frontier has never been properly demarcated and the high-altitude terrain is often disorientating, the practice for decades was for neither side to use weapons.
Indo-Chinese relations are at a multi-decade low after PLA troops annexed 60 square kilometres of Indian territory in Ladakh in May.
At least 20 Indian soldiers were killed during violent clashes in June - the first casualties along the LAC in over 45 years - and one Indo-Tibetan special focus soldier died in August.
The two countries have failed to agree a permanent demarcation of their 3,488 kilometre border after fighting a brief war in 1962 and fist-fighting between troops on patrol has broken out intermittently since.
This year's dramatic uptick in conflict comes as China asserts its authority in the region amidst strengthening India-US ties, which Beijing views as a threat.
On Saturday, both countries had agreed to diffuse tensions along the LAC but heavy reinforcing has recommenced today after Monday's clash.
Separately, the Chinese Foreign Ministry has said five missing Indian citizens who disappeared in the eastern Indian state of Arunachal Pradesh close to the LAC are not in Chinese custody.