National Security Agency leaker Edward Snowden said today that rather than helping combat terrorism, the U.S. government's massive surveillance programs have led to "tremendous intelligence failures" and may have contributed to allowing the deadly Boston Marathon bombing to have taken place.

"We're monitoring everybody's communications, instead of suspects' communications," Snowden said during a live video conference at Austin's popular South by Southwest festival. "That lack of focus has caused us to miss leads that we should've had. Tamerlan Tsarnaev, one of the Boston bombers, the Russians had warned us about him… And if we hadn't spent so much on mass surveillance, if we had followed the traditional models, we might've caught him."

In 2011 Russian intelligence requested the FBI and CIA to separately help them investigate Tamerlan's possible ties to Islamic extremism. Months later, the FBI closed their investigation after concluding that Tamerlan did not pose a threat.

In April 2013, authorities allege Tamerlan and his little brother Dzhokhar set off a pair of bombs near the finish line of the Boston Marathon, killing three and injuring more than 260 others. Tamerlan was killed in a shootout with police days later, and Dzhokhar was arrested and has pleaded not guilty to terrorism-related charges. He could face the death penalty. The New York Times reported weeks after the bombing that the FBI concluded there was little the Bureau could have done to prevent the attacks.

RELATED: Intense Security Planned for Boston Marathon, 'No Specific Threat'

Snowden also referred to Umar Farouk Abdulmutallab, the young man who tried to blow up an airplane over Detroit on Christmas Day 2009 with explosives hidden in his underwear. Abdulmutallab's father attempted to warn U.S. officials that he had concerns about his son prior to the attack, but despite his father's worry, Abdulmutallab was not placed on a no-fly list. The other passengers of the plane that Christmas Day were only saved when they noticed Abdulmutallab attempting to light his explosives and subdued him themselves.

A spokesperson for the CIA, the agency which was approached by Abdulmutallab's father, called into question Snowden's general theory told ABC News the agency doesn't "put a lot of stock in Snowden's tips for improving our intelligence capabilities."

"The Agency is a versatile global organization that is more than capable of addressing a range of national security threats simultaneously and it does so every day," the spokesperson said. "Anyone suggesting otherwise is seriously misinformed."

In testimony before lawmakers, the heads of American law enforcement and intelligence agencies have defended various NSA surveillance programs, and the head of the NSA, Gen. Keith Alexander, claimed the surveillance programs had played a role in the thwarting of more than 50 terrorist "terror-related activities" worldwide. In the case of Abdulmutallab, a Senate Intelligence Committee report in 2010 criticized the NSA for not doing enough - for not pursuing "potential collection opportunities that could have provided information" on the would-be terrorist.

However, last December an outside expert panel convened by the White House to review the surveillance programs found that the NSA's most controversial collection program - so-called Section 215 for the relevant portion of the Foreign Intelligence Surveillance Act - was "not essential to preventing attacks" and presented a "lurking danger of abuse." The panel made 46 recommendations to how the government should change the way it watches the world, some of which the White House has said it will follow, while others remain under consideration.

READ: President Obama's Own Experts Recommend End to NSA Phone Data Spying

Snowden said he was speaking at SXSW, his first live video conference since fleeing to Moscow, because he wanted to talk directly to the tech developers that could make communications more secure through their programs, rather than waiting on a lumbering government to change policy. With enhanced and encrypted communication tools, Snowden said it would be too difficult for the NSA to sweep up information on everyone's communications and therefore would be forced to put their resources into spying on people they believe actually pose a threat.

Snowden, a former contractor with Booz Allen who worked at a secure NSA facility in Hawaii, revealed himself as the source of the massive NSA leak last June while in hiding in Hong Kong. From there, he slipped to Moscow where he was granted temporary asylum. A slew of media reports on the NSA's foreign and domestic programs has followed, with no end in sight.

Snowden has been charged in the U.S. with espionage-related crimes and has said he believes he will not be afforded a fair trial should he return. And though privacy advocates call him a hero while critics deride him as a traitor, Snowden said he would do it all over again if he had to.

"When it comes to, would I do this again, the answer is 'Absolutely, yes,'" Snowden said today. "Regardless of what is done to me… This is something we have the right to know."

Representatives for the FBI did not immediately respond to request for comment for this report. The NSA declined to comment.

[Editor's Note: A previous version of this report incorrectly stated that Edward Snowden said he didn't mind major telecom companies, rather than the NSA, temporarily holding on to customers' communications information, as proposed by the White House panel. Snowden was speaking more broadly about major corporations being less of a threat to individuals when it comes to surveillance because they do not have the power to imprison or even kill their customers, or to hide behind "state secrets" arguments in the courts. Snowden was not speaking in reference to the White House panel's specific recommendation regarding metadata collection.]

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