Headley has pleaded guilty to making surveillance videos in preparation for the siege of India's financial capital and to involvement in a plot to attack a Danish newspaper over cartoons depicting the Prophet Muhammad.
As part of Headley's plea bargain agreement, the United States agreed not to extradite him to India, Pakistan or Denmark for the charges for which he has admitted guilt.
Indian Home Minister Palaniappan Chidambaram said Friday that India had yet to receive permission from U.S. authorities to speak with Headley or his wife and would press for his extradition to India.
Although Headley could not be extradited under the terms of his plea bargain, it might be possible if new charges are brought against him at a future date, Blake told reporters.
The 60-hour Mumbai siege left 166 people dead. Nine attackers – all based in Pakistan – were killed, while a tenth suspect is on trial in Mumbai.