The effort collapsed after agents couldn't determine a way for Lon Snowden to speak to his son once he arrived in Moscow, he told The Washington Post in an interview published Tuesday.
"I said, 'I want to be able to speak with my son. ... Can you set up communications?' And it was, 'Well, we're not sure,'" Snowden told the Post. "I said, 'Wait a minute, folks, I'm not going to sit on the tarmac to be an emotional tool for you.'"
The Post said it wasn't clear why the negotiations failed and the FBI declined to comment.
Lon Snowden said he didn't go to Moscow on his own because he wasn't sure if he would have access to his son. He said he and his son communicated through unspecified "intermediaries" as recently as a few days ago.
Lon Snowden defended his son, who some have labeled a traitor, saying Edward Snowden grew up in a patriotic family in suburban Maryland and "loves this nation."
Lon Snowden, a retired U.S. Coast Guard officer, said he didn't know why his son leaked information about the far-reaching National Security Agency monitoring program. He told the Post his son appeared troubled when the family was together in April, but "We had no idea what was coming."
"If you could say there was a tipping point, I would say it was what happened in the last six to nine months of this nation," he said.
The 30-year-old Edward Snowden, an NSA contractor, admitted to leaking documents about the NSA cellphone and Internet surveillance programs to Britain's Guardian and the Post.
Edward Snowden, charged in the United States with theft and espionage, is seeking temporary asylum in Russia and has been holed up in the transit station of Moscow's Sheremetyevo International Airport since he arrived in late June from Hong Kong. U.S. officials have condemned the leaks and said the programs he exposed are legal and have federal court supervision.
Lon Snowden said he was shocked when his son admitted to being the leaker.
"I was as surprised as the rest of America. I was stunned," he said.
"As a father, it pains me what he did. But as an American citizen, I am absolutely thankful for what he did," Lon Snowden said.
"I believe he is comfortable with who he is. Yes, I am certain. I know my son. He knows he has done the right thing."