Describing terrorism as a "shared challenge" for India, Pakistan, Afghanistan and the United States, Washington says it had some "specific concerns" in warning Americans about possible terror attacks in well-known markets in New Delhi.
State Department spokesman P J Crowley Wednesday called the warden message issued by the US embassy in New Delhi "a prudent warning" but would give few details.
"There are some specific concerns we have but I'm not going to go into them from the podium," Crowley said.
"It [the warden message] was just a caution to our citizens within the American community that we have growing concerns about terrorism and it might affect both Indian citizens and American citizens."
"We are very mindful that in the attacks on Mumbai, Americans died and Indians died and citizens of other countries as well," Crowley said. More than 160 people died in the November 2008 terror attack in Mumbai.
"So it was a - just a prudent warning about - to our citizens as they continue their business in the countries," he said.
Asked if the warning was linked to the recovery of more than 50 pounds of explosive material in Bangalore, Crowley said: "I can't get any more specific than I did. Obviously, this is a shared challenge for India, for Pakistan, for Afghanistan, for the United States. We are concerned about attacks that can impact people there."
"We are concerned about attacks that emanate from the region to other parts of the world, including - affecting us here. This is a shared challenge, one that we take seriously, one that we know India and Pakistan take seriously.
And we will continue our cooperation with both countries," he said.
"Whether we have specific threat information against those markets or just we have indications that the threat involves public spaces, I just can't comment," Crowley said.
On intelligence sharing among US, India and Pakistan against counter-terrorism operations, he said: "I can't really talk about intelligence sharing between India and Pakistan.
"I'll leave it to those two countries. I know that they have had high-level conversations in recent months on terrorism issues."
US has a "strategic relationship with both India and Pakistan," he said noting "Intelligence and counterterrorism is a significant element of that."
"We do share information. We do work cooperatively because it is a threat that affects each of us. So this underscores the fact that we have ongoing concerns about those who would try to disrupt favourable trends regarding security and cooperation in the region, and we will continue to do everything possible to prevent these attacks from taking place."