US Vice-President Mike Pence and Indian Prime Minister Narendra Modi discussed regional security, defence and trade on the sidelines of the Asean Summit yesterday.
"The two leaders reiterated the importance of the US-India strategic partnership and of advancing our shared vision of a free and open Indo-Pacific," the White House said.
Indian Foreign Secretary Vijay Gokhale said Mr Modi had suggested that India's vision of an Asean-centred Indo-Pacific, presented during his address at the Shangri-La Dialogue in June, had gained traction and could be advanced at today's East Asia Summit.
"We conveyed to Vice-President Pence that this vision of Indo-Pacific was gaining acceptability and that we should utilise the upcoming East Asia Summit to further build up on that," he said.
The United States has pushed for a "free and open" Indo-Pacific partly in response to China's growing footprint in the region.
But India remains wary of being drawn into any US strategy that might involve the containment of China, although both nations have stepped up bilateral defence ties and military exercises.
Mr Modi also asked the US to explore making defence equipment in India not just for its own market but with an eye on regional markets. They also discussed counter-terrorism cooperation and ways to boost trade, with India indicating interest in expanding imports of oil and gas from the US, currently valued at US$4 billion (S$5.5 billion).
Mr Pence also had discussions with Vietnamese Prime Minister Nguyen Xuan Phuc, affirming the growing bilateral relationship and the US commitment to a "free and open South China Sea".
The White House said: "Noting the 25th anniversary of normalised diplomatic relations in 2020, they agreed to strengthen bilateral cooperation across economic and security realms, including by addressing barriers to trade and by enhancing maritime security cooperation in the South China Sea."
Vietnam, along with Brunei, Malaysia, the Philippines and Taiwan, is contesting China's claims in the waterway.
Mr Pence also met Myanmar leader Aung San Suu Kyi as well as Indonesian President Joko Widodo.
Mr Pence and Mr Joko agreed to strengthen cooperation across security and economic issues, including upholding freedom of navigation in the South China Sea, improving the humanitarian situation for the Rohingya and increasing two-way trade.
The White House said: "They agreed to promote shared principles, values and norms for a free and open Indo-Pacific based on Asean centrality, and looked forward to celebrating the 70th anniversary of bilateral ties in 2019."