(NBC NEWS) -- In Washington today, lawmakers who support N.S.A. phone logging and internet monitoring warned the revelation of those programs tipped off would-be terrorists who are already changing how they communicate.
The N.S.A. will not say how the bad guys are changing up what they doing to avoid detection, and will not detail, yet, how they say these programs worked to prevent attacks.
But they did say one program was put to work last April.
After the Boston bombings, and the Tsarnaev Brothers were identified as suspects
The N.S.A. was able to use the phone data it's collecting to go back and see who the suspects talked to to be sure no one else was involved no more bombing planned.
That's what the head of N.S.A. told senior lawmakers.
But he warned U.S. enemies are adapting, now that they know phone and internet use can be tracked.
And the lawmakers warned, we're in danger
"By the exposure of this program and the changes that we can already see being made by those folks who wish to do us harm," said Congressman Mike Rogers who chairs the House Intelligence Committee.
Ed Snowden, who revealed the N.S.A. programs, today said the U.S. government is hacking into Hong Kong and Chinese computers.
The FBI director confirmed the U.S. wants Snowden extradited.
"These disclosures have caused significant harm to our safety and our nation," said Robert Mueller.
N.S.A Chief Alexander said now that the programs are public he will prove they worked.
"But we don't wanna risk Americans lives in doing that. So what we're being is very deliberate in this process so that we don't end up causing a terrorist attack by giving out too much information," said National Security Agency Chief General Keith Alexander.
But many in Congress now say N.S.A is taking in too much information.
"I believe we are actually more secure when we narrow our focus and target specific suspects. Despite mining billions of American phone calls we still had the boston bombing," said Kentucky Republican Senator Rand Paul.
Some Tea Party Republicans, like Paul, are allied in that debate with liberal Democrats with centrists in both parties including President Obama defending the N.S.A