"I think the US and India increasingly are natural allies. We share a growing convergence of our values and our interests. Our peoples and our governments are engaged together in virtually every field of human endeavour.

"After more than a decade of cooperation, it is clear there's strong and bipartisan support in both countries to cooperate even more closely," Blake said.

Referring to his recent trip to India, he said he heard from India interlocutors that sky is the limit to the US-India relationship. "Actually, with our growing space cooperation, we may have to extend that particular boundary of cooperation," he said.

He said the US response to the Mumbai attacks reinforced the unprecedented cooperation that has taken place between the US and India on terror financing, law enforcement, training and information-sharing.

In recent months, the director of the Federal Bureau of Investigation, the CIA chief, the chairman of the Joint Chiefs of Staff and National Security Adviser all have visited India to underline and strengthen that cooperation.

Blake said there is room for expanded defence cooperation between the United States and India. As India's economy grows, it has sought to modernise its military, and US technology can and should be a part of that modernisation.

"We are working hard to conclude bilateral agreements such as the end-use monitoring agreement that will help to ensure that defence sales and military-to-military cooperation can continue their positive trajectory," he said.