The father of Edward Snowden, the former U.S. intelligence contractor who leaked details of NSA surveillance programs, said Thursday, in a letter to Attorney General Eric Holder, that his son may agree to return to the U.S. if he was assured that his constitutional rights would not be compromised.

Lonnie Snowden’s attempt to broker a deal with U.S. authorities has come at a time when his son’s efforts to win an asylum to evade U.S. prosecution continue to be unsuccessful, prolonging his stay at a Moscow airport transit area.

In the letter written by a lawyer on Lonnie Snowden’s behalf, he expressed “reasonable” confidence that his son would return to his homeland if he would not be placed under detention before trial, would not be subjected to a gag order, and would be tried in a venue of his choosing, Reuters reported.

“I am concerned about those who surround him,” Lonnie Snowden told NBC in an interview on Friday. “Wikileaks -- if you look at past history -- their focus isn't necessarily the Constitution of the United States. It’s simply to release as much information as possible. So that alone is a concern for me.”

“He has betrayed his government, but I don't believe that he's betrayed the people of the United States,” Lonnie Snowden said.

He said he has not been in touch with his son since April, NBC reported.

“I love him. I would like to have the opportunity to communicate with him. I don't want to put him in peril,” he said in the interview.

The Justice Department has not commented on Lonnie Snowden’s proposal.

Edward Snowden fled to Hong Kong in May, shortly after he leaked details of surveillance programs carried out secretly by the National Security Agency.

The government of Ecuador, which has already provided asylum for WikiLeaks founder Julian Assange at its London embassy, has yet to answer Snowden’s request for refuge.

Venezuelan President Nicolas Maduro has signaled the possibility of granting asylum to Snowden, although he has not taken any steps in this regard.