NSA Director Keith Alexander has been misleading the public by saying that the NSA's shadowy surveillance programs, exposed by whistleblower Edward Snowden this month, have thwarted terrorist attacks, Guardian reporter Glenn Greenwald told CNN's Piers Morgan Tuesday night.

“It’s not that they’re lying. It’s misleading,” Greenwald said to Morgan, referring to recent claims made by Alexander that the NSA’s "dragnet" surveillance programs, have specifically helped stopped more than 50 terrorist attacks.

Greenwald emphasized that there is yet to be any evidence that shows the NSA has thwarted a terrorist attack with data collected through the programs exposed by Snowden:

There is zero evidence … that this program of collecting everybody’s phone records as opposed to just the terrorists’ in any way keeps us safer or is necessary to stop terrorist plots.

Likewise, Senators Mark Udall and Ron Wyden, both members of the Senate intelligence committee, released a statement last week stating that they are not convinced by the NSA director's claims:

We have not yet seen any evidence showing that the NSA's dragnet collection of Americans' phone records has produced any uniquely valuable intelligence.

And the Guardian pointed out Tuesday that one of Alexander's recent examples has holes in it. Alexander claims that he NSA's surveillance systems thwarted an alleged planned bombing of the New York Stock Exchange through monitoring the communications of Missouri-based suspect Khalid Ouazzan.

However, as the Guardian pointed out, Ouazzani has never been accused of the crime that the NSA supposedly averted.

In Greenwald's interview, he pointed out that it is harder to thwart plots with these kind "dragnet programs" used by the NSA “because they’re collecting so much stuff they don’t even know what they have.”

However, Alexander's and Obama's recent justifications are nothing new, Greenwald emphasized—this is what the government does every time “somebody exposes what they want to hide from the people over whom they’re ruling."

"People in power like to keep people over whom they rule in fear, because that way they will submit...to whatever it is they want them to do."

"They are just reciting from the same handbook they always use," Greenwald added.

Watch the interview, which includes Daniel Ellsberg, below: