"The relationship that we are building with India is not to the exclusion of other countries," Mattis told reporters.
"It is specifically designed for inclusion using a rules- based order that any nation that is living by the traditional rules of non-interference in other states in today's age of anti-terrorism, they will not find this relationship in any way adversarial," Mattis said in response to question.
He lauded India for contributing tens of thousands of dollars for building infrastructure in Afghanistan and training Afghan officers.
"They've been a great asset, and we would see them continuing along the lines they have already chosen, and looking for any other areas that they may believe appropriate to the relationship with Afghanistan," he added.
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In the security sphere, India has been providing training to the Afghan security forces.
"It's building the underpinnings of the government that actually builds the affection and respect of the people of Afghanistan to a government that delivers. It's absolutely critical to security that the people of Afghanistan feel hope for the future. No nation has probably contributed more bilaterally than India in building that hope," he said.
Responding to a question on Pakistan, Mattis said it has come out recently again saying that they are fighting the terrorists. "I think Pakistan will find nothing out of line with India and the US alignment in the same fight," he said.
Mattis said the new Afghanistan-Pakistan strategy started from a regional point of view. "We did not start it with Afghanistan and work out. We actually started with South Asia, as a region, and worked to refine how we would deal with the terrorists problem in Afghanistan," he explained.
"So, that is the message, one of inclusion, not one of exclusion, of rules-based order, of a broad mutual cooperation against terrorists, and certainly of strategic convergence right now with India, between India and the United States," the top American defense official said.