FCC Chairman Kevin Martin turned down a congressional request for an investigation as a top intelligence official concluded it would "pose an unnecessary risk of damage to the national security," according to a letter National Intelligence Director Michael McConnell sent to Martin on Tuesday.
Intelligence officials "support your determination not to initiate an investigation," McConnell wrote to Martin.
At issue are reports last year that some big telephone companies allowed the U.S. government access to millions of telephone records for an antiterrorism program.
The reports have prompted scrutiny by the House Energy and Commerce Committee. Democratic Rep. Edward Markey, the chairman of a key Energy and Commerce subcommittee, asked Martin to investigate.
In his response, Martin included Tuesday's letter from McConnell. A representative for the FCC declined further comment.
Markey, of Massachusetts, said McConnell's stance was "unsurprising given that this administration has continually thwarted efforts by Congress to shed more light on the surveillance program."
"I believe the agency could conduct its own examination of such reports in a way that safeguards national security," Markey said in a statement.
The Energy and Commerce Committee also asked AT&T, Verizon Communications and Qwest Communications International on Tuesday to describe how U.S. government agencies sought to obtain information about customer telephone and Internet use.