Hanoi's need for bolstered maritime defenses against an increasingly assertive China in the territorially disputed South China Sea is expected to be high on the agenda when Indian Prime Minister Narendra Modi visits Vietnam later this week.

Professor Sukh Doe Muni, fellow at the Institute for Defense Studies and Analyses in New Delhi, says the Indian leader's arrival Friday comes as "the question of South China Sea has come up in a big way."

A ship (top) of Chinese Coast Guard is seen near a
FILE - A Chinese Coast Guard ship (top) is seen near a Vietnam Marine Guard vessel in the South China Sea, about 210 km (130 miles) off shore of Vietnam, May 14, 2014.

"Narendra Modi's visit actually is the strong indication of India showing its friendship, camaraderie, solidarity with Vietnam, particularly at the time when Vietnam is facing lots of pressure in the region from China," said the former senior Indian diplomat, who once worked in Southeast Asia.

Modi's Hanoi stopover, which will make him the first Indian prime minister to visit Vietnam in over a decade, comes one day before he'll join the Group of 20 summit in Hangzhou, China.

According to Ngo Xuan Binh, director of the Institute of Indian and Southwest Asian Studies in Hanoi, defense is a key part of "traditional" Hanoi-New Delhi relations, and there are mixed reactions among the Vietnamese public.

"Some say Modi's visit to Vietnam before participating in the G20 summit shows how important Hanoi is to New Delhi, and it's also a signal to China," he said. "However, others say the visit has little impact on China, as it is a big partner of Beijing in many aspects."

India's Brahmos supersonic cruise missiles, mounte
FILE - India's Brahmos supersonic cruise missiles, mounted on a truck, pass by during a full dress rehearsal for the Republic Day parade in New Delhi, January 23, 2006.

But Binh also says the recent tribunal ruling in The Hague, which dealt a legal blow to China's maritime claims, may bring India and Vietnam into closer diplomatic orbit. Vietnamese experts on Indian affairs, for example, have cited sources claiming that Hanoi entered high-level negotiations in June with New Delhi to buy BrahMos cruise missiles — the world's highest-velocity anti-ship cruise missile currently in operation — which has prompted concerns from Beijing.

According to IHS Janes, "talks in Hanoi included the option of stationing a team of Indian technicians in the Southeast Asian country to offer the Vietnamese assistance in using the [BrahMos] system," and that New Delhi officials suggest the weapons transfer might be imminent.

Vietnamese media quoted Indian Ambassador to Hanoi P. Harish as saying this week that New Delhi also hopes to reach agreements with Hanoi in areas of cooperation such as science, technology, defense and security. But it is unclear whether the two sides will sign any deal on BrahMos.

The Stockholm-based International Peace Research Institute recently reported that Vietnam was the eighth-largest arms importer in the world from 2011 to 2015, up from 43rd in the previous five-year period, and that India is one of the largest weapons exporters to Vietnam.

Rising tensions over the South China Sea maritime region in recent years have driven Vietnam to buy arms to defend itself.

This report was produced in collaboration with VOA's Vietnamese service.