Edward Snowden, the former National Security Agency contractor who revealed the US government's top-secret monitoring of Americans' phone and Internet data, has said the government's "litany of lies" about the programmes compelled him to act.
In a question-and-answer session with readers and journalists on website of the UK’s Guardian newspaper on Monday, Snowden urged President Barack Obama to "return to sanity" and roll back the surveillance effort.
Snowden also talked about his motivations and reaction to the debate raging about the damage or virtue of the leaks. Snowden remains in hiding, reportedly in Hong Kong.
"I did not reveal any US operations against legitimate military targets," he said.
"I pointed out where the NSA has hacked civilian infrastructure such as universities, hospitals, and private businesses because it is dangerous. These nakedly, aggressively criminal acts are wrong no matter the target."
Snowden said disillusionment with Obama contributed to his decision, but there was no single event that led him to leak details about the vast monitoring of Americans' activity.
"It was seeing a continuing litany of lies from senior officials to Congress - and therefore the American people – and the realisation that Congress ... wholly supported the lies," said Snowden, who had worked at an NSA facility in Hawaii as an employee of contractor Booz Allen Hamilton before providing the details to the Guardian and the Washington Post.
Snowden referred to US Director of National Intelligence James Clapper's testimony to Congress in March that such a programme did not exist, saying that seeing him "baldly lying to the public without repercussion is the evidence of a subverted democracy. The consent of the governed is not consent if it is not informed."
The Justice Department has opened a criminal investigation into Snowden's actions, and US officials promised last week to hold him accountable for the leaks.
'No fair trial'
However, Snowden said the US government made it impossible for him to receive a fair trial.
"The US government, just as they did with other whistleblowers, immediately and predictably destroyed any possibility of a fair trial at home, openly declaring me guilty of treason and that the disclosure of secret, criminal and even unconstitutional acts is an unforgivable crime. That's not justice," he wrote on the online forum.
His actions ignited a renewed debate about privacy rights and national security, and in the US Snowden has been called both a hero and a traitor for his actions.
Former US Vice President Dick Cheney was the latest to call Snowden a traitor, but Snowden called that a badge of honour.
"Being called a traitor by Dick Cheney is the highest honour you can give an American, and the more panicked talk we hear from people like him ... the better off we all are," Snowden said.