Cell phone
Wyden is worried the government could be intercepting the phone calls of Americans unrelated to terrorist investigations. Samantha Celera

A government intelligence-gathering program aimed at overseas terror suspects may be improperly collecting communications from innocent Americans, two Democratic senators are warning.

Senators Mark Udall of Colorado and Ron Wyden of Oregon, who have regularly criticized the secrecy enshrouding government surveillance programs, are expressing fresh objections as the Senate moves to reauthorize the Foreign Intelligence Surveillance Act of 2008. A section of the law empowers the government to monitor phone calls and emails from terror suspects living abroad.

Wyden blocked an extension of the law on Monday, using a parliamentary procedure known as a hold that prevented the legislation from getting a Senate floor vote.

Since all of the communications collected by the government under section 702 are collected without individual warrants, I believe that there should be clear rules prohibiting the government from searching through these communications in an effort to find the phone calls or emails of a particular American, unless the government has obtained a warrant or emergency authorization permitting surveillance of that American, Wyden said in a statement explaining his decision.

Udall concurred with Wyden, asking for more information about the law's application so that Congress can consider whether privacy protections should be clarified or strengthened.

Udall and Wyden were rebuffed a year ago when they asked the Obama administration to estimate how many Americans had their communications reviewed under the law. They also floated an unsuccessful amendment that would have barred searches that applied to Americans' correspondences.

Wyden and Udall resisted renewal of the PATRIOT Act last summer, saying Americans would be stunned if they knew how the law was put to use. They have kept up the criticism, writing in a recent letter to Attorney General Eric Holder about a significant gap between what most Americans think the law allows and what the government secretly claims the law allows.