One year after revealing himself as the source of the biggest intelligence leak in US history, Edward Snowden appeared in a long network television interview on Wednesday to describe himself as an American patriot and to make the case that his disclosures were motivated by a desire to help the country.



In his most extensive public comments to date Snowden sought to answer critics who have said his actions damaged US national security or that the threat from the secret government surveillance he revealed was overblown. Snowden was interviewed by the NBC News anchor Brian Williams, who travelled to Moscow for the meeting.



Snowden defended his decision to leak documents to the press, instead of restricting his complaints to internal channels, and explained why he had decided for the moment not to travel back to the United States to face criminal charges.



“If I could go anywhere in the world that place would be home,” Snowden told Williams. “I’ve from day one said that I’m doing this to serve my country … I don’t think there’s ever been any question that I’d like to go home.”



Snowden said he had not second-guessed his decision, however, to release an estimated 1.7m top secret government documents. “My priority is not about myself,” Snowden said. “It’s about making sure that these programs are reformed – and that the family that I left behind, the country that I left behind – can be helped by my actions.”



The interview, which took place at Kempinski Hotel in Moscow last week, followed months of negotiations between the news network and representatives of Snowden. The conversation, which was held in a library and lasted more than four hours, was billed as Snowden's first interview with a US television network.



Snowden has regularly participated in interviews over the last year, although never on such a large stage, or on one as likely to bring his words – and his argument – into American living rooms. NBC Nightly News, which ran clips from the interview, drew about 8.4m total viewers per night in May.



On Wednesday Snowden, 30, described for the first time his experience of the 9/11 terror attacks and talked about his views on the threat of terrorism.



“I’ve never told anybody this,” he said. “No journalist. But I was on Fort Meade [Maryland] on September 11th. I was right outside the NSA. So I remember – I remember the tension of that day. I remember hearing on the radio the planes hitting. And I remember thinking my grandfather, who worked for the FBI at the time, was in the Pentagon when the plane hit it.



“I take the threat of terrorism seriously. And I think we all do. And I think it’s really disingenuous for the government to invoke and sort of scandalize our memories, to sort of exploit the national trauma that we all suffered together and worked so hard to come through to justify programs that have never been shown to keep us safe, but cost us liberties and freedoms that we don’t need to give up and our constitution says we should not give up.”

Snowden said he did not consider himself blameless. “I think the most important idea is to remember that there have been times throughout history where what is right is not the same as what is legal,” he said. “Sometimes to do the right thing, you have to break a law.”



In a Pew Research poll of Americans earlier this year 57% of 18 to 29-year-olds said Snowden’s leaks had served the public interest but respondents 65 and over disagreed. A majority of respondents in older age groups supported prosecuting Snowden, while the 18-29 group split 42-42% on the question.

As much as he wanted to return home, Snowden said, he did not plan “to walk into a jail cell”. He repeated a view explained elsewhere by his legal counsel that the charges he faces under the 1917 Espionage Act would not allow him to mount a defense that he had acted in the public interest.



“These are things that no individual should empower himself to really decide, you know, ‘I’m gonna give myself a parade,’” Snowden said in reply to a question about how he judged his actions. “But neither am I going to walk into a jail cell, to serve as a bad example for other people in government who see something happening, some violation of the constitution, and think they need to say something about it.”



In the year he has lived in Russia as a fugitive from US law, Snowden said, he had not met President Vladimir Putin. “I have no relationship with the Russian government at all,” he said.



NBC News said it had confirmed “with multiple sources” that before he took the story to the press Snowden had raised a concern about possibly illegal surveillance on at least one occasion with intelligence agency superiors. Snowden said he had advanced his concerns on multiple occasions, even sending emails to the office of the NSA general counsel, and that the NSA would have a paper trail. The NSA has denied Snowden took such steps.



Snowden said he remained comfortable with the decision he made.



"I may have lost the ability to travel but I've gained the ability to fall asleep at night and know I've done the right thing and I'm comfortable with that.”



• This story was amended on 29 May to clarify that Snowden did use internal government channels to raise his concerns.