Two Indian officials say Chinese troops are deploying fiber-optic networks in the disputed hotspot, despite efforts to reduce confrontation.
"Our biggest concern is that Chinese soldiers have deployed a fiber-optic network south of Pangong Tso Lake in the Ladakh region to ensure high-speed communications. They are making this move at breakneck speed."
Another official said the network helps forward troops maintain confidential communications with rear bases.
A third Indian official said the fiber-optic deployment was discovered after satellite images showed unusual lines in the sand, apparently trenches for cable burying, in the desert south of Pangong Tso Lake.
China's Ministry of Foreign Affairs and Defense Ministry did not comment on the information yet.
"Radio communications can be intercepted and eavesdropped, while optical cables are highly secure. The Indian army still relies on radio communications but it's all encrypted," said a former official.
Tensions on the Indian and Chinese border have escalated since late April and early May, culminating in a brawl on June 15, killing dozens of soldiers on both sides.
India and China have recently sent reinforcements to the border, despite previously agreeing to reduce frontline forces.
Tensions continued to escalate when China on September 8 accused Indian soldiers of firing only in the one-day scuffle at the border, in violation of the no-fire agreement between the two sides.
Bilateral tensions are expected to cool down after the withdrawal agreement was agreed by the two foreign ministers in Moscow.
The location has occurred in clashes between Indian and Chinese soldiers in recent months.