China has accused Indian forces of crossing into its territory along their disputed border, reports AP.
India also fired warning shots at a Chinese patrol in a move it called a "serious military provocation" and a violation of their agreements, said China.
On the other hand, India on Tuesday rejected Chinese allegations of violating border agreements and accused Chinese troops of firing in the air during a face-off on their tense de facto border, reports Reuters.
"It is the PLA that has been blatantly violating agreements and carrying out aggressive manoeuvres, while engagement at military, diplomatic and political level is in progress," the Indian army said in a statement.
It said Chinese soldiers tried to close in on a forward Indian position in the Ladakh sector in the western Himalayas and when were met by Indian troops, the PLA fired a few rounds in the air.
The nuclear-armed rivals have been engaged in a tense standoff in the cold-desert Ladakh region since May.
Their defense ministers met Friday in Moscow in the first high-level direct contact between the sides since the standoff began.
China's western military command said the incursion occurred Monday along the southern coast of Pangong Lake in the area known in Chinese as Shenpaoshan.
On the Indian side, the area is known as Chushul where the two countries local military commanders have held several rounds of talks to defuse the tense standoff.
After shots were fired, Chinese forces took "necessary measures to stabilize and control the situation," the command said, in the statement citing spokesman Zhang Shuili.
It demanded the Indian forces withdraw and investigate the move to open fire.
There was no word of casualties on either side.
Late last month, India says its soldiers thwarted the Chinese military's moves "to change the status quo" in violation of a consensus reached in past efforts to settle the standoff. In turn, China also accused Indian troops of crossing established lines of control.
The activity last month and on Monday were alleged to have occurred in Chushul area on the southern bank of Pangong Lake, a glacial lake divided by the de facto frontier and where the India-China faceoff began on its northern flank in early May.
The standoff escalated to a medieval, nighttime clash June 15 that was the deadliest conflict in 45 years between the nuclear-armed rivals. According to Indian officials, Chinese troops atop a ridge at the mouth of the narrow Galwan Valley threw stones, punched and pushed Indian soldiers down the ridge at around 4,500 meters (15,000 feet). India said 20 of its soldiers were killed, including a colonel. China did not report any casualties.
The disputed and undemarcated 3,500-kilometer (2,175-mile) border between India and China, referred to as the Line of Actual Control, stretches from the Ladakh region in the north to the Indian state of Arunachal Pradesh. According to China, the frontier is about 2,000 kilometers (1240-mile) and claims entire Arunachal Pradesh as its territory.
The nuclear-armed Asia giants fought a border war in 1962 that also spilled into Ladakh and ended in an uneasy truce. The two countries have been trying to settle their border dispute since the early 1990s, without success.
India unilaterally declared Ladakh a federal territory and separated it from disputed Kashmir in August 2019, ending its semi-autonomous status. The move further strained the relationship between New Delhi and Beijing, which raised the issue at international forums including the UN Security Council.
In a symbolic move amid soaring tensions, India has banned scores of Chinese-owned apps, including TikTok, citing privacy concerns that it said pose a threat to India's sovereignty and security.