Washington — The Senate on Thursday passed an extension of a key surveillance authority that allows U.S. intelligence agencies to spy on foreigners without a warrant, the latest in a back-and-forth with the House over the expiring program.

The program, known as Section 702 of the Foreign Intelligence Surveillance Act, or FISA, is set to expire at 12 a.m. Friday without an extension by both chambers. The Trump administration and members of both parties in Congress argue that Section 702 is a key national security tool, and that its lapse would leave intelligence agencies in the dark about threats around the world.

Senators unanimously approved a bill that would extend the program for 45 days. The extension now goes to the House.

Section 702 was initially set to expire on April 20, but both chambers agreed to push the deadline back 10 days shortly before the authority lapsed.

The House passed a three-year extension on Wednesday, but the bill included a provision that would ban a central bank digital currency. House leaders added that language to placate conservative holdouts, many of whom oppose extending Section 702 without reforms to the program. Proponents of reforms have demanded a requirement that law enforcement obtain a warrant to search U.S. citizens' communications that get swept up in foreign intelligence collection.

But the ban on a central bank digital currency is a nonstarter in the Senate, where Majority Leader John Thune has called it a "poison pill." Instead, the upper chamber moved forward with the 45-day extension to buy time to reach a broader agreement.

The Senate's move means the House must also approve the short-term extension before midnight to prevent Section 702 from lapsing. Both chambers are on recess next week, adding to the pressure to get a deal done.

House Speaker Mike Johnson indicated earlier in the day that the lower chamber would wait to see what the Senate produces. 

"We have done our job. The Senate needs to do theirs," Johnson said, while acknowledging attendance could become difficult as lawmakers leave town. "This is our last legislative day," he added, warning that he "will have a jailbreak" if the issue isn't resolved before the end of the day.