Speaking at the annual Shangri-La Dialogue here, US Defence Secretary General (Retd) James Mattis also said while competition between the US and China was bound to occur, the conflict between the world's two largest economies was not "inevitable".
"Respecting freedom of navigation and adhering to international norms [are] essential for peace and economic growth in the inter-linked geography of the Indo-Pacific," Mr Mattis said.
PM Modi has termed sea lanes passing through the strategic South China Sea as the "main arteries" of global trade.
He has maintained that India supports freedom of navigation and seeks "utmost respect" for international law, amid China's muscle flexing in the region.
Outlining India's principled position on the dispute over the South China Sea, PM Modi in his address at the 11th East Asia Summit (EAS) in September last year had said "the threat or use of force" to resolve would complicate matters affecting peace and stability.
China claims sovereignty over all of South China Sea.
Vietnam, Malaysia, the Philippines, Brunei and Taiwan have counter claims.
China is engaged in hotly contested territorial disputes in both the South China Sea and the East China Sea. Beijing has built up and militarised many of the islands and reefs it controls in the region.
Both areas are stated to be rich in minerals, oil and other natural resources. They are also vital to global trade.
Mr Mattis in his speech titled 'The United States and Asia- Pacific Security' also expressed reservation about Chinese actions that impinge on the interests of the international community.
"We cannot accept Chinese actions that impinge on the interests of the international community, undermining the rules-based order that has benefited all countries represented here today including, and especially, China," he told some 500 delegates at the Shangri-La Dialogue which focus on defence and security.
"While competition between the US and China, the world's two largest economies, is bound to occur, conflict is not inevitable," he said in his speech.
"We seek a constructive, results-oriented relationship with China. We believe the United States can engage China diplomatically and economically to ensure our relationship is beneficial not only to the United States and China but also to the region and to the world," Mr Mattis said.