The information emerged after the US Department of Justice disclosed the contents of a July 23 letter, which had generated fevered speculation on both sides of the Atlantic.
"The United States will not seek the death penalty for Mr. Snowden should he return to the United States. The charges he faces do not carry that possibility, and the United States would not seek the death penalty even if Mr. Snowden were charged with additional, death penalty-eligible crimes,” said the letter, which was addressed to Russian Justice Minister Aleksandr Konovalov.
In the letter, the US also promised that Snowden would receive a public jury trial in the civil courts, and would not be subjected to anything but "voluntary questioning” in the lead-up to his trial.
"Mr. Snowden will not be tortured. Torture is unlawful in the United States,” wrote the attorney general.
Holder’s letter explicitly tackles Snowden’s previously expressed fears.
"I believe that, given these circumstances, it is unlikely that I would receive a fair trial or proper treatment prior to that trial, and face the possibility of life in prison or even death," Snowden wrote in the cover letter for the multiple asylum applications he submitted around the world over the past few weeks.
"These claims are entirely without merit,” insists Holder. "These assurances eliminate these asserted grounds for Mr Snowden’s claim that he should be treated as a refugee or granted asylum.”
"Our focus in this specific case is having Mr. Snowden returned to the United States, and we still feel Russia has the opportunity to do that and to take the right steps,” the US State Department spokeswoman Jen Psaki told journalists at a daily press briefing.
Edward Snowden currently remains in the international transit zone of Moscow’s Sheremetyevo airport, waiting for his temporary asylum application to be reviewed.
Snowden faces three charges of theft of government property, unauthorized communication of national defense information, and willful communication of classified communications intelligence information to an unauthorized person. The maximum tariff for the latter two crimes, which are considered more serious, is ten years in prison.
Moscow and Washington do not have an extradition agreement, although Moscow has handed over US citizens on a case-by-case basis in the past.
Snowden’s father speaks out against son’s "demonization”
Edward Snowden's father has blasted US politicians for failing to admit oversteps in their surveillance programs, which prompted his son to share the information on all-encompassing PRISM with the press earlier this summer.
"I am extremely disappointed and angry. I’ve watched closely the 36 members on the two intelligence committees and the American people don’t know the whole truth. The truth is coming,” Lon Snowden told NBC’s Today program.
"There has been a concerted effort by many of these congressmen to demonize my son, to focus the issue on my son and not to talk about the fact that they had a responsibility to ensure that these programs were constitutional. They’ve either been complicit or negligent.”
Snowden, who has publicly supported his son throughout the last few weeks, also accused US politicians of serving private interests.
"Many of those people will go back and say we must fund these obscenely expensive programs that drive up massive profits for companies like Booze Allen Hamilton [the contractor that employed Edward Snowden]...It’s all about the money.”
Lon Snowden admitted that he has not directly communicated with Edward, but that he relies on an intermediary from whistleblower website Wikileaks to pass along messages. He added that both of them are unbending in their political convictions, despite accusations of treason.
"This story is far from done," said Snowden. "I believe when my son takes his final breath, whether it’s today or 100 years from now, he will be comfortable with what he did.”