State Department's John Kirby said India and US are natural allies and share democratic traditions.
China need not fear from stronger India-US ties after the two countries inked a key logistics defence pact, the US State Department said.
"Broadly speaking, a deepening, stronger, more cooperative bilateral relationship with India is not something that anybody should fear or worry about," State Department spokesman John Kirby said.
Mr Kirby was responding to China's reaction to the defence pact between India and the US that will enable their militaries to use each other's assets and bases for repair and replenishment of supplies.
"We both are democracies, we both have incredible opportunities and influence on the global stage, and a better relationship between the US and India is not just good for our two countries, not just good for the region, it's good for the world," he said.
"There's already a tremendous partnership between the US and India which cuts across quite a few sectors and it's not just security and defence related. It's economic, trade and information and technology sharing," Mr Kirby added.
"It is a pretty full and complete, comprehensive relationship and it's one that we are committed to deepening and strengthening and I think that's why the secretary of defence's counterpart is here. It's why the secretary of state and the secretary of commerce, (Penny) Pritzker, are there in New Delhi," he said.