The National Security Agency investigated fewer than 300 phone numbers in 2012, according to a three-page US government document.
The report, made public by the Senate Intelligence Committee on Sunday, says those numbers were checked against a large phone record database kept by the NSA, a process that in 2009 helped authorities foil New York's 2009 subway attack.
Without providing specifics, the report echoes statements made by the NSA that its two controversial data-collection programs helped stop attacks on US soil and abroad.
"In recent years, the intelligence gathered under them has contributed to the disruption of dozens of potential terrorist pots here in the homeland and in more than 20 countries around the world,” the documents said.
Earlier in June, Edward Snowden, a former NSA contractor, revealed himself to be the source of reports by the UK's Guardian newspaper and The Washington Post about NSA programs that monitor data from companies like Facebook and Google.
The news comes as Denis McDonough, White House chief of staff, said on CBS's "Face the Nation" on Sunday that President Barack Obama does not think the NSA's secret program violates Americans' privacy rights.
Watch part of McDonough's interview here: