President Obama urged the Senate on Tuesday to work during its recess to renew the government's authority to track terrorists through phone data before it expires at midnight Sunday.
Obama urged the chamber's Republican leaders to pass a House-approved measure that would let the National Security Agency retain access to the phone records, but with changes that end the more controversial practice of bulk data collection by the government.
"This needs to get done," Obama told reporters in the Oval Office.
"I strongly urge the Senate to work through this recess and make sure that they identify a way to get this done," he added, calling it "necessary to keep the American people safe and secure."
The Senate rejected two bills last week that would have continued the program, including the one passed by the House and backed by the White House to renew but limit the government's access to phone data.
As lawmakers left the Capitol for their week-long Memorial Day break, Senate Majority Leader Mitch McConnell (R-Ky.) warned that the Senate "better be ready next Sunday afternoon to prevent the country from being endangered by the total expiration of the program."
Sen. Rand Paul of Kentucky, a Republican who has long opposed the NSA program and used procedural moves last week to keep senators from reaching a deal to extend it, said Tuesday that the phone data collection is itself a breach of the 4th Amendment's protection against unreasonable searches.
"The abuse of the 4th Amendment is the actual bulk collection of records; there's the potential for abuse," he said, warning against a possible chilling effect on the right to dissent.
But in preparation for the possibility that the powers will expire altogether, the NSA began shutting down over the weekend its program for tracking terrorists in the U.S. through phone records. The program gives the government access to records that show the number dialed, duration, date and time for most telephone calls made in the U.S.
The government searches the information for connections to the phone numbers of known terrorists or terrorism suspects. Last year the government conducted an estimated 300 searches as part of the program.
Intelligence officials warn that if Congress doesn't come up with a partial renewal, there will be a significant gap in the data that goes uncollected but might be needed in future searches.
Obama said the House measure would be effective.
"The House of Representatives did its work and came up with what they've called the USA Freedom Act, which strikes an appropriate balance," Obama said. "Our intelligence communities are confident that they can work with the authorities that are provided in that act."