Indian and Chinese soldiers were involved in an altercation in the western Himalayas on Tuesday, Indian sources said, further raising tensions between the two countries, which are already locked in a two-month standoff in another part of the disputed border.

A source in New Delhi, who had been briefed on the military situation on the border, said soldiers foiled a bid by a group of Chinese troops to enter Indian territory in Ladakh, near the Pangong lake.

Some of the Chinese soldiers carried iron rods and stones, and in the melee there were minor injuries on both sides, the source said.

China’s defense and foreign ministries did not immediately respond to request for comment.

The two sides have frequently accused each other of intrusions into each other’s territories, but clashes are rare. The Indian military declined to comment on the incident.

“There was an altercation near the Pangong lake,” said a police officer in Srinagar, the capital of India’s Jammu and Kashmir state, under which the area falls. An army source in Srinagar also spoke of an altercation following what he called a Chinese army “incursion in Pangong lake area”.

The two armies are already engaged in a standoff in the Doklam plateau further east, in another part of their 3,500 km (2,175 mile) unmarked mountain border.

China has repeatedly asked India to unilaterally withdraw from the Doklam area, or else face the prospect of an escalation. Chinese state media have warned India of a fate worse than its crushing defeat in a brief border war in 1962.

The trouble started in June when India sent troops to stop China building a road in the Doklam area, which is remote, uninhabited territory claimed by both China and India’s ally Bhutan.

New Delhi said it sent its troops because Chinese military activity in Doklam, near the trijunction of the borders of India, China and Bhutan, was a threat to the security of its own northeast region. But Beijing has said India had no role to play in the area and diplomatic efforts to defuse the crisis have not made much headway.

An Indian government minister said efforts were continuing to find a way to end the standoff. The minister, speaking on condition of anonymity because of the sensitivity of the issue, said Prime Minister Narendra Modi’s government had no choice but to act to stop the Chinese road activity in the region because it had come too close for comfort.