As calls on Capitol Hill and across the country intensify to rein in surveillance programs, a senior U.S. intelligence official says the federal government's tracking of phone calls and Internet activity helped foil a 2009 terror plot on the New York City subways, the Associated Press reported.

The official's remark follows Michigan Republican Rep. Mike Rogers, chairman of the House Intelligence Committee, saying Thursday the programs thwarted a terrorism plot.

However, civil libertarians and some members of Congress say the National Security Agency surveillance programs to hunt terrorists were too broad and collected too much information about innocent Americans.

News of the programs -- first about the phone calls, then about the Internet activities -- was revealed late Wednesday and Friday.

In one program, the NSA collected daily records of millions of phone calls made and received by U.S. citizens not suspected of any wrongdoing.

The senior U.S. intelligence official who asserted Friday that the phone records program together with other technical intercepts thwarted the subway plot would not provide other details. The official was not authorized to discuss the plot publicly and requested anonymity.

Afghan-American Najibullah Zazi pleaded guilty in the 2009 plot, saying he had been recruited by al Qaeda in Pakistan.

The break in that case came, according to court documents and testimony, when Zazi emailed a Yahoo address seeking help with his bomb recipe.

CBS News has also reported that the so-called PRISM program, that tracked Internet activity, helped foil the plot to detonate bombs in the Grand Central and Times Square subway stations during rush hour.

At that time, British intelligence officials knew the Yahoo address was associated with an al Qaeda leader in Pakistan. That's because, according to British government documents released in 2010, officials had discovered it on the computer of a terror suspect there months earlier.

Meanwhile, Capitol Hill Democrats and Republicans are already considering ways to rein in the Obama administration’s data-mining programs.

"This is a dragnet," Rep. Jim Sensenbrenner, R-Wis., told Fox News on Friday.

Because the NSA and British intelligence work so closely together and so little is known about how the NSA monitors email traffic, it's possible that both agencies were monitoring the Yahoo address at the time Zazi sent the critical email in 2009.

What's unclear, though, is how the phone program aided the investigation, which utilized court-authorized wiretaps of Zazi and his friends.

While some security-focused lawmakers defended the program, others warned that they plan to start reassessing the Patriot Act as early as this month, with the goal of potentially curbing the data collection.

Sensenbrenner, who wrote the 2001 law that provides the legal authority for such efforts, said he and House Judiciary Committee Chairman Bob Goodlatte, R-Va., are prepared to change the relevant sections of the law. The Patriot Act provisions are scheduled to expire in 2015 without reauthorization. Sensenbrenner said if lawmakers need to change the law before then, "we will have hearings and we'll do that."

Democratic Sens. Dick Durbin, Illinois, and Mark Udall, Colorado, made similar calls over the past couple of days for changes to the Patriot Act.

President Obama said Friday that the programs have made a difference in tracking terrorists and are not tantamount to "Big Brother."

The president acknowledged the U.S. government is collecting reams of phone records, including phone numbers and the duration of calls, but said this does not include listening to calls or gathering the names of callers.

"You can't have 100 percent security and also then have 100 percent privacy and zero inconvenience,” he said. “We're going to have to make some choices as a society."

However, the president said he welcomes a debate on that issue.

The Associated Press contributed to this report.