Vice President Hamid Ansari's visit to Vietnam witnessed crucial discussions on several strategic issues, but both countries remained tight-lipped about their differences with China over the South China Sea issue.

Realising the sensitivity of the issue, Ansari and the team of diplomats from the Ministry of External Affairs, who were accompanying him, were coy about discussing the South China Sea and China's objections to India's oil and gas exploration in the region.

During an interaction with the media persons travelling with him on board the special aircraft, Ansari mentioned that India's work in oil and gas exploration in the region is continuing but went no further specifically on the issue.

He also said strategic issues were discussed between him and the top Vietnamese leadership and India will continue to engage in continuing "across the board cooperation".

The two countries entered into a strategic relationship in 2007.

Asked if China's objections to India exploring oil and gas in the South China Sea came up during his discussions with Vietnam, Ansari said, "Not as far as our oil exploration is concerned. There is an on-going problem between China and Vietnam about the sea boundary. That is something about which the whole world is concerned about because it is something that will have an impact on movement of shipping lanes and trade... Everything."

Ansari maintained that India's view all along on the issue is that it has to be settled "within the framework of existing international norms and settled peacefully through negotiations".

During the four-day state visit of the Vice President of India to Vietnam, Hanoi maintained that there should be freedom of navigation in the South China Sea.

India finds a natural partner in Vietnam on the issue as it has openly spoken against China at forums like the recent India-ASEAN summit.

Vietnam is of the view that any disputes in the region should be dealt with under the six-point formula of ASEAN and the 1982 UNCLOS Agreement.

The two countries are also working on increasing cooperation on national defence and security issues.

India has been providing training to Vietnamese forces.

The Indian navy has also made port calls in Vietnam.

Defence and strategic dialogues have taken place on several occasions between the two countries.

Vietnam also expressed support to India's bid to become a Permanent member of the expanded UN Security Council.