"Obviously, we do have an extradition treaty with India, but how that will work going forward, I think that’s premature," Crowley, told reporters at a news briefing.

Early this week, FBI formally charge sheeted Headley for being allegedly involved in the Mumbai terrorist attack.

"The FBI and Justice Department continue to share information with our foreign and domestic law enforcement partners in the Headley investigation," Dean Boys, spokesman, National Security Division of the US Department of Justice said.

"As a matter of long-standing policy, we never comment on extradition matters. Headley remains charged in federal court in Chicago and the investigation continues."

In New Delhi, Union Home Secretary Pillai, told reporters that once India completes its probe into Headley's links with the Mumbai terror attacks, the government will seek his extradition.