India's Prime Minister Narendra Modi and his Vietnamese counterpart Nguyen Xuan Phuc discussed issues related to the South China Sea as well as defence links between the two countries during a virtual summit this week.
The two leaders underscored the importance of "self-restraint" and "non-militarisation" of the South China Sea while drawing up a road map for closer defence ties.
The South China Sea featured prominently in Monday's talks, which came at a time when both countries have seen a downturn in their respective ties with China.
Mr Modi stressed that the Code of Conduct negotiations on the South China Sea should not prejudice the interest of other countries in the region, said Ministry of External Affairs Secretary (East) Riva Ganguly Das.
Asean and China have been seeking to resume talks on a maritime code of conduct.
Separately, the two countries released a document called India-Vietnam Joint Vision for Peace, Prosperity and People, with two paragraphs dedicated to the South China Sea issue.
"Both leaders underscored the importance of non-militarisation and self-restraint in the conduct of all activities by claimants and all other states, and avoidance of actions that could further complicate the situation or escalate disputes affecting peace and stability," said the document.
India is embroiled in its worst border troubles with China in over four decades. It has accused China of changing the status quo on the Ladakh region border, with negotiations so far failing to resolve all differences.
Vietnam has competing claims with China near the Paracel Islands in the South China Sea.
The country has objected to Chinese military drills in the disputed area, accused Beijing of intimidating its fishermen and of advancing territorial claims during the Covid-19 pandemic.
Analysts note that there are many areas of convergence between India and Vietnam, which will also take their seats in the United Nations Security Council next month.
"Among Asean member states, convergence with Vietnam is greatest. Vietnam has been much more open and explicit in courting countries like India and trying to diversify the relationship bilaterally," said Professor Harsh Pant, director, studies and head of the strategic studies programme at the Observer Research Foundation in New Delhi.
Though India is not directly involved in the territorial dispute, China has expressed irritation with its oil exploration activities in the area. One of the oil blocks in which India is involved falls partly in territory that has been claimed by China.
Business ties between India and Vietnam have grown over the years, with bilateral trade touching US$12.34 billion (S$16.46 billion) in 2019-2020.
Vietnam is India's 18th largest trading partner globally and the fourth largest within Asean, after Singapore, Indonesia and Malaysia.
On Monday, Mr Modi also invited Vietnamese companies to invest in India and highlighted the urgent need for a long-overdue review of the Asean-India Trade in Goods Agreement as a concrete step towards revitalising economic engagement between India and Vietnam as well as the larger Asean region.
He also highlighted the importance of ties in his opening remarks at the summit.
"We see our relationship with Vietnam from a long-term and strategic view... Our partnership can make a significant contribution in maintaining stability and peace in the region," said Mr Modi.
Defence, analysts have said, is emerging as a key area of cooperation.
The two countries also signed nine MOUs, including a framework for promoting cooperation between the defence industries of the two countries.
India also handed over the first of 10 high-speed guard boats which are being manufactured under a US$100 million defence line of credit extended in 2014 by India to Vietnam.
"There is skill transfer and technology transfer. Manufacturing and capacity transfer. I guess that's the harbinger for future projects," said China expert Professor Srikanth Kondapalli from the Jawaharlal Nehru University.
He noted that although tensions with China formed a common ground, the two countries also had historical ties.