By Dow Jones Business News, March 25, 2015, 10:25:00 AM EDT

The National Security Agency will cease collecting bulk telephone metadata if Congress doesn't reauthorize or replace parts of a federal law that expires at the end of May, a White House spokesman said Wednesday.

President Barack Obama has called for replacing the existing program, first revealed by former NSA contractor Edward Snowden, with a more narrowly targeted system that he says would better safeguard privacy but allow law-enforcement and intelligence agencies to collect certain data they believe necessary for national security.

The provision that would expire is Section 215 of the USA Patriot Act.

"Allowing Section 215 to sunset would result in the loss, going forward, of a critical national security tool that is used in a variety of additional contexts that don't involve the collection of bulk data," White House spokesman Ned Price said. "That is why we have underscored the imperative of congressional action in the coming weeks, and we welcome the opportunity to work with lawmakers on such legislation."

There had been speculation that the White House might nevertheless continue the bulk telephone data collection even if the law were allowed to sunset.

The White House's position was first reported by Reuters.

The program has allowed the NSA to collect telephone data for millions of Americans, primarily records of who calls whom, and the length of each call.

Congress is split over whether to allow the program to continue. Many Republicans want the program reauthorized, as they say it helps intelligence agencies detect threats against the U.S. But many Democrats and a number of Republicans say it raises constitutional and privacy concerns, particularly as data is collected for people who haven't been accused of wrongdoing.

House Permanent Select Committee on Intelligence Chairman Devin Nunes (R., Calif.) told reporters Tuesday he supported the extension of the program, and complained that there was a misunderstanding about how the program worked and how it prevented terror attacks.

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NSA to Halt Telephone Data Program If Congress Doesn't Act