The memorandum of understanding on mutual logistics support is the first such major agreement that Vietnam has signed with any country.
The prime minister's meetings with Abe and Turnbull came a day after he held "very expansive" talks with US President Donald Trump on intensifying overall security and defence cooperation, particularly in the Indo-Pacific region where China is strengthening its military build up.
Prime Minister Narendra Modi on Saturday visited the historic Pagoda temple in Hanoi and the stilt house where revered Vietnamese leader Ho Chi Minh lived, apart from enjoying fishing with his Vietnamese counterpart Nguyen Xuan Phuc.
The PM held bilateral meetings with three ASEAN leaders, including his Vietnamese counterpart Nguyen Xuan Phuc and Myanmar's State Counsellor Aung San Suu Kyi, and discussed key bilateral and regional issues.
The 25th anniversary of ASEAN-India Dialogue Relations is being marked. And invitations were sent by the Indian government to all ASEAN leaders for the Republic Day function.
Countries that have signed the RCEP agreement can start negotiations with India for joining the pact once New Delhi submits a written request stating its intention for the same, according to a declaration. On November 4 last year, India walked out of mega free trade agreement RCEP (Regional Comprehensive Economic Partnership) as negotiations failed to address New Delhi's outstanding issues and concerns. The remaining 15 member countries have signed RCEP agreement and have stated that the pact would remain open to India.
The South-East Asian country is a growing market for sponsors such as brewer Heineken and will give the region four races on the calendar again after the departure of Malaysia last year.
PM Modi to travel to Vietnam before going to China to attend G20 summit.
In a veiled reference to China's aggressive military behaviour, Defence Minister Rajnath Singh on Thursday said exercising self-restraint in the conduct of activities and avoiding actions that may further complicate situation will go a long way in bringing sustained regional peace.
Defence, security, science and technology, trade and culture are some of the issues on the plate for the talks.
'India does not wish to remain silent in improving its strategic space so that its leverage to counter China's expansionist designs is maintained, besides enabling it to play a responsible role from a position of strength for peace and stability in Asia,' points out Dr Rajaram Panda.
New Delhi is quietly reclaiming its space in Asia by forging alliances with China's neighbours. In a way, India is converting its much-talked about Act East Policy to Engage East practice.
India on Saturday extended $500 million (Rs 3,328 crore) Line of Credit to Vietnam for facilitating deeper defence cooperation with the south east Asian nation, as the two countries elevated their ties to a Comprehensive Strategic Partnership to respond to emerging regional challenges.
In a strong message to China, India and ASEAN on Thursday called for a "full and effective" implementation of the understanding between the parties involved in the South China Sea dispute, while stressing on maritime security and freedom of navigation in the critical sea lanes.
Had India agreed to join the trade pact, Indian markets would have been flooded with cheap Chinese products.
The majestic Rajpath saw a scintillating display of India's military might as the country celebrated its 69th Republic Day on Friday, with the leaders of all the 10 countries of the ASEAN attending the parade. Take a look here.