The rivalry between India and China is heating up as the heavyweight economies face territorial tensions on both land and sea.

A fierce border stand-off in Bhutan’s Doklam region — triggered by a Chinese road construction project in a disputed area and a Bhutanese request for Indian help — is now entering its second month with soldiers from both sides engaged in skirmishes. But a new confrontation in the relationship is arising as New Delhi grows concerned about a Chinese naval presence in its own backyard: the Indian Ocean.

“As the [Doklam] crisis stretches on, China is likely to seek ways to pressure India, both on the border and elsewhere, and this will compound the cycle of competition that is already well underway,” Shashank Joshi, research fellow at the Royal United Services Institute, said in a recent note published by the Lowy Institute.

Indeed, the recent joint naval drills between the U.S., India and Japan — known as the Malabar exercises — were widely interpreted as a coordinated response to perceived Chinese expansion in the Indian Ocean.

In the run-up to Malabar, Indian media reported of a surge in Chinese naval vessels around the area, noting sightings of 13 to 14 units in two months. Those included Luyang III class destroyers, hydrographic research vessels, an intelligence-gathering ship and a submarine.

Beijing does operate in the area for its “Belt and Road” initiative, an infrastructure program that involves developing port facilities in the Indian Ocean with Pakistan and Sri Lanka. India isn’t a member of the initiative and has repeatedly indirectly criticized the program for violating Indian sovereignty.

“China’s naval presence in the Indian Ocean is showing signs of a qualitative shift,” Joshi said, noting the mainland’s growing patrols and the July 12 dispatch of Chinese troops to a military base in Djibouti — Beijing’s first long-term foreign military deployment in almost 60 years.

“This Chinese facility is not just a platform from which China can project initially modest power into the western Indian Ocean, but will also justify and support a greater volume and pace of other patrols through the eastern and central Indian Ocean,” Joshi added.

New Delhi is certainly paying close attention to those developments, as reflected by the Malabar drills.

“With over 20 ships, including two submarines and over 100 aircraft and helicopters involved in complex maneuvers, [India’s] strategic messaging to China seemed more than clear,” Abhijit Singh, head of the Maritime Policy Initiative at think tank Observer Research Foundation, wrote in a note.

“Indian commentators cast Malabar as a strategic precursor to a more proactive sea-denial strategy aimed at challenging People’s Liberation Army Navy ships in the Indian Ocean.”

The situation draws parallels with Beijing’s behavior in a different body of water. The world’s second-largest economy has been creating artificial islands in contested sections of the South China Sea. But unlike that international waterway, the Indian Ocean isn’t a site of overlapping sovereign rights, meaning Prime Minister Narendra Modi’s efforts to counter the mainland on his home turf may not be sustainable.

“There is something essentially flawed about the idea that Indian naval power can prevent Chinese warships and submarines from accessing India’s near-seas. Modern-day trading nations regard the oceans as a shared global common, with equal opportunity rights for all user states,” said Singh.