A recently uncovered jihadist-inspired plot by a young American to massacre lawmakers in the US Capitol was discovered thanks to the government's controversial surveillance programmes, House Speaker John Boehner claimed on Thursday.
"We would never have known about this had it not been for the FISA (Foreign Intelligence Surveillance Act) programme and our ability to collect information on people who pose an imminent threat," Boehner told reporters.
FISA allows US spy agencies to conduct electronic espionage internationally as well as on Americans suspected of involvement in terror-related activities. It has been embroiled in controversy following revelations in 2013 about the extent of US dragnet surveillance including bulk collection of data on Americans.
"Our government does not spy on Americans unless there are Americans who are doing things that frankly tip off our law enforcement officials to an imminent threat," Boehner said at a Republican retreat in Hershey, Pennsylvania.
"And it was our law enforcement officials and those programmes that helped us stop this person before he committed a heinous crime in our nation's capital."
Boehner did not explain what FISA provisions helped foil the plot, saying "we'll let the whole story roll out."
His abridged account differs from public statements by the Justice Department and Federal Bureau of Investigation, which announced on Wednesday that an FBI informant and the suspect's public Twitter account were key to the man's arrest.
The Justice Department announced that Ohio man Christopher Cornell, 20, was charged with attempted murder of US officers and employees and possessing a firearm to carry out violent acts.
It said Cornell this week allegedly made final plans to go to Washington and set off bombs, having purchased two semiautomatic rifles and 600 rounds of ammunition before he was arrested by FBI agents, according to the affidavit.
The complaint said Cornell had opened a Twitter account under the pseudonym Raheel Mahrus Ubaydah, and posted messages supporting Islamic State militants.
"It was far more than just that," Boehner stressed about the social media connection, without providing details.
In August, Cornell was approached by an FBI informant, and the suspect told him that he "considered the members of Congress as enemies and that he intended to conduct an attack on the US Capitol," the complaint said.
The FBI said he planned to "build, plant and detonate pipe bombs at and near the US Capitol, then use firearms to shoot and kill employees and officials."
In June 2013, former national security contractor Edward Snowden revealed the extent to which the National Security Agency scoops up Americans' telephone data, triggering surveillance reform efforts that are ongoing.
Boehner's remarks should buttress arguments of some lawmakers opposed to any major NSA overhaul.
Critics have deemed FISA, amended after the 9/11 attacks of 2001, too permissive.
Some of its most controversial elements expire in June, setting up an opportunity for Congress to amend, renew or repeal the legislation.
The Capitol plot, and last week's indictment of a bartender who threatened to kill Boehner, has elevated security awareness in Washington.
Law enforcement "told us on day one it was the most highly targeted terrorist spot in the world, and we're seeing that play out," Congressman Jason Chaffetz told reporters.