The global threat from Islamic militant groups based in the region was on top of the agenda of U.S. envoy Richard Holbrooke, during his discussions with top security officials in New Delhi.
After meeting Indian Foreign Minister Pranab Mukherjee, he told reporters that India, the United States and Pakistan face a common threat from Islamic militancy.
Holbrooke spoke on the day the Pakistan government signed an agreement with Islamic hardliners that is to lead to the enforcement of Sharia law in Pakistan's Swat valley.
"What happened in Swat demonstrates a key point, and that is that India, United States, India and Pakistan all have a common threat now. For the first time in 60 years since independence, your country and Pakistan and the U.S. all face an enemy that poses a threat to our leadership, our capitals and our people," he said.
Holbrooke is in charge of U.S. strategy in South Asia under President Barack Obama, and this is his first tour to the region. He said he brought no "message, or guidance", but wanted to hear New Delhi's views on a wide range of issues.
Indian officials are believed to have shared their view that Pakistan is the epicenter of terrorism, and pressure must be put on Islamabad to dismantle what New Delhi calls the "infrastructure of terrorism" in the country.
New Delhi is also unhappy with the military aid given by the United States to Pakistan to fight militants.
Observers say part of Holbrooke's mission to New Delhi was to try to reduce the distrust that has grown between India and Pakistan following the terror attacks in Mumbai last November. Last week, Islamabad admitted the attacks were partly planned on its soil. India says Pakistan was slow in making the admission.
The United States is also seeking a larger role for New Delhi in the development of Afghanistan. India has already built highways and participated in other projects.
Relations between India and the United States have improved significantly in recent years. Most observers expect that the ties will continue to strengthen under the new U.S. government.