Admiral Scott Swift, Commander, Pacific Fleet, also pitched for India signing the three contentious defence foundational agreements that Washington is keen on.
Talking about the growing Chinese activities in the Indian Ocean, he wondered why would any country deploy nuclear submarines for anti-piracy operations.
India security agencies are concerned about such activities of the Chinese Navy but China claims the submarines are part of their anti-piracy fleet.
"There is lack of transparency, lack of understanding of the intent," Swift said speaking to a select group of reporters.
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He said it is for India to decide what role it wants to play in the maritime waters but pointed out that US would be ready for more naval exercises.
He cited the recent Malabar naval exercise between India, US and Japan and said Washington wants the exercise to be inclusive rather than exclusive.
Talking about the maritime disputes in Asia, Swift said that in 2012, the International Tribunal for the Law of the Seas decided a maritime border dispute between Bangladesh and Burma that benefited both.
He said that two years later, the Permanent Court of Arbitration, resolved Bangladesh's western maritime border dispute with India two years later.
"India demonstrated regional leadership by agreeing to arbitration with its smaller neighbour and by accepting the ruling," he said adding that this could be a role model for others, in an indirect reference to the dispute in South China Sea. China has territorial water disputes with Vietnam, the Philippines, Japan and some other ASEAN countries.
The American side had raised the issue of signing of Communications and Information Security Memorandum of Agreement (CISMOA), Logistics Support Agreement (LSA) and Basic Exchange and Cooperation Agreement (BECA) during the recent visit of Defence Minister Manohar Parrikar to the US.
While the previous UPA government had refused to sign these, sources said Parrikar has asked the US to address India's concerns over these agreements for holding further talks, particularly on CISMOA and BECA.