Facebook, Google, Apple and three other leading technology companies on Thursday called for substantial reforms to the U.S. government’s surveillance programs, which have drawn new scrutiny in the aftermath of revelations by former National Security Agency contractor Edward Snowden.

The letter, sent to top members of the Senate Judiciary Committee, endorses greater transparency in surveillance programs, long a goal for tech companies that must comply with government data requests from around the world. Yet it also goes further, urging U.S. lawmakers to enact reforms that would “include substantial enhancements to privacy protections and appropriate oversight and accountability mechanisms for those programs.”

It specifically “applauds” a bill sponsored by Sen. Patrick J. Leahy (D-Vt.) and Rep. F. James Sensenbrenner Jr. (R-Wis.) that would end the “bulk” collection of the communications records of millions of Americans and create a privacy advocate to represent civil liberties concerns before the Foreign Intelligence Surveillance Court.

“We urge the Administration to work with Congress in addressing these critical reforms that would provide much needed transparency and help rebuild the trust of Internet users around the world,” the letter said.

The letter underscored the urgency felt by technology companies amid the worldwide reaction to news about U.S. government surveillance. Foreign governments have threatened new legal restrictions on how companies operate in their countries, and industry officials worry that some users may abandon services provided by American companies out of concern about spying by the NSA.

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The signers included Microsoft, Yahoo and AOL.