US whistleblower Edward Snowden would not face the death penalty or be tortured and would have all the protections of the US civilian court system if he were sent home, the chief US prosecutor wrote in a letter to his Russian counterpart, according to Reuters news agency.

In the letter dated July 23 and released on Friday, the US Attorney General Eric Holder wrote to the Russian Justice Minister Alexander Konovalov that he sought to dispel claims about what would happen to the former US security contractor Snowden if Russia handed him over to face charges of illegally disclosing government secrets about surveillance programmes.

Snowden, 30, has been stuck at a Moscow airport for more than a month while he searches for a country that will grant him asylum and avoid the criminal charges.

Russia has refused to hand over Snowden, who leaked details of secret US electronic surveillance programmes to British and US media, to the United States, and is considering a temporary asylum request.

"We believe that these assurances eliminate these asserted grounds for Mr. Snowden's claim that he should be treated as a refugee or granted asylum, temporary or otherwise," Holder wrote in the two-page letter.

Holder, the head of the US Justice Department and an appointee of President Barack Obama, also promised that Snowden could have a lawyer with him for any questioning.

Snowden's supporters have worried he could face the same fate as Private First Class Bradley Manning, the US soldier accused of providing documents to WikiLeaks, the anti-secrecy group. Upon his arrest, Manning was placed in solitary confinement for up to 23 hours a day with guards checking on him every few minutes.

"Torture is unlawful in the United States," Holder wrote, without explicit reference to Manning. "If he returns to the United States, Mr. Snowden would promptly be brought before a civilian court."

Russia-US ties

Meanwhile, Kremlin’s spokesman, Dmitry Peskov, said on Friday that the Russian President Vladimir Putin had expressed "strong determination" not to let ties with Washington suffer over the dispute, "no matter how the situation develops".

Peskov said Putin was not involved in talks over the fate of Snowden. But he reiterated Moscow's stance that Russia "did not hand over, does not hand over and will not hand over anybody".

He added that Russia's federal security service FSB and its US counterpart, the FBI were in talks over the matter.