It also justified its decision not to seek death penalty for the Pakistani-American terrorist, saying it was done in view of his willingness to cooperate with law enforcement authorities to help bring the perpetrators to justice and help prevent other terror strikes.
"The 35-year sentence without parole imposed on David Coleman Headley marks another step in US efforts to bring to justice those responsible for the 26/11 Mumbai terrorist attacks. This sentence reflects both severe punishment for Headley's role in the heinous 26/11 crimes and a decision by the US Department of Justice not to seek the death penalty," a statement from the US Embassy said.
This decision was taken because of Headley's willingness to cooperate with law enforcement authorities -American, Indian and others - to help bring the perpetrators to justice and prevent other terrorist attacks, it said.
It also said Headley had provided information that was of "substantial value in our efforts to combat international terrorism and to save lives" apart from testifying against a co-conspirator, Tahawwur Rana, who is now serving a 14-year sentence in federal prison.
Headley provided extensive detail about accused terrorist leader Ilyas Kashmiri and his network, it said, adding Headley also answered questions from Indian law enforcement authorities.
Apart from assisting US investigators in bringing criminal charges against five other terrorists, Headley also provided US law enforcement authorities with details about the structure, personnel, methods, abilities and plans of the terrorist organization, Lashkar-e-Toiba.
"The US and India counter-terrorism cooperation is stronger than ever. The FBI provided its expertise and testified in the Indian prosecution of Ajmal Kasab. We are working together to see that those responsible for 26/11 and other acts of terrorism are brought to justice, wherever they may be," the statement said.
Headley was yesterday sentenced to 35 years in jail by a US Court for helping plot the 2008 Mumbai terror attacks but escaped death penalty under a deal with the US government over which the judge had serious reservations.