Forty-seven U.S. senators attended a closed-door briefing with top national security officials Thursday to learn more about how telephone and Internet-tracking programs used by the National Security Agency have thwarted multiple terrorist attacks -- details that lawmakers said the general public will begin learning more about by Monday.

Sen. Dianne Feinstein (Photo by Alex Wong/Getty Images) Sen. Dianne Feinstein (Photo by Alex Wong/Getty Images)

Sen. Dianne Feinstein (D-Calif.), who chairs the Senate Intelligence Committee, said it is taking longer to release the information as top NSA officials work to ensure that any information released publicly is as accurate as possible.

Gen. Keith Alexander, who leads the NSA, "wants to be exact," Feinstein said.

"What he wants to give us are the cases where this stopped a terrorist attack, both here and in other places. And he wants to be exact about the detail and we should have that Monday," she said.

Once the information is released, "We'll make an assessment based on what's come out," she added.

Among other things, Feinstein said she will push for legislation that bars contractors from "handling highly classified technical data."

Sen. Bob Corker (R-Tenn.) said he and others at the briefing agreed that more information should be released in order to better inform the public about the programs.

"We were given some very specific and helpful information about how these programs have helped keep the American people safe," he said.

"I can't imagine any United States senator sitting through a briefing like we just had and not feeling thankful for the efforts that NSA and others put forth," Corker added.