Khurshid has written the letter to Clinton for extradition of the two before their sentencing there in Jan 2013, official sources said here yesterday.
According to sources, India is hopeful that the US would take a favourable decision on its request which was sent in the first week of Nov. New Delhi is awaiting a response from Washington.
During her visit here last month, US Under Secretary for Political Affairs Wendy Sherman had said India's request for extradition of Headley was under consideration and a decision could be taken soon.
Though, India had limited access to 52-year-old Pakistani-American Headley, who recced the 26/11 Mumbai terror attack targets for the LeT but it has so far not been able to quiz his Pakistani-Canadian businessman friend Rana.
New Delhi's requests for access to Headley's wife Shazia Gilani, his girlfriend Portia Peter, one more female friend are also yet to be acceded by Washington.
Sources also said talks were being planned between the Ministry of Home Affairs and the US Department of Justice to discuss a series of issues, including Headley and Rana.
"Not only Headley and Rana, we are talking to the US on a number of issues very seriously," sources said.