Intelligence chiefs and senior administration officials are pushing for a surveillance law, set to expire at the end of the year, to be signed into law on a permanent basis.

Director of national intelligence Dan Coats, NSA director Mike Rogers, acting FBI director Andrew McCabe, and deputy attorney general Rod Rosenstein testified at a Senate Intelligence Committee hearing on Wednesday, unified behind a legislative effort to ensure the government maintains its sunsetting foreign surveillance and data collection capabilities.

The so-called Section 702 statute, named after its place in the law books, is set to expire at the end of the year, five years after it was first reauthorized after its debut in 2008 under the FISA Amendments Act (FAA).

The intelligence chiefs are pushing for Congress to renew it for the first time since the Edward Snowden disclosures in 2013, which invoked uproar among privacy advocates and rights groups.

Coats, in his opening remarks, confirmed that the Trump administration is pushing for a "permanent reauthorization" of Section 702, which would prevent it from expiring. It followed an op-ed for The New York Times by homeland security advisor Tom Bossert, who said that the statute was crucial in helping to "thwart terrorist attacks around the world." Section 702, which authorizes the collection of data on foreign persons overseas who use US tech and communications services, was the legal basis for the so-called PRISM surveillance program, which reportedly taps data from nine tech titans including Apple, Facebook, Google, Microsoft and others.

Those companies have been some of the loudest voices behind the effort to reform the government's surveillance powers.

In an open letter, Amazon, Facebook, Google, Microsoft, and Twitter -- and others -- called on the House Judiciary Committee, currently charged with the statute's reauthorization efforts, to reform the statute to ensure greater transparency and judicial oversight of the law.

That reform effort appears to have fallen on deaf ears. The government has so far gained the support to reauthorize the statute on a permanent basis from over a dozens senators -- including every Republican on the Senate intelligence panel, according to Reuters.

But the move to support the legislative effort was spurned as "out of touch" by the American Civil Liberties Union, who argued that despite the government's assertions that Americans are not directly targeted, that an unknown number of US citizens -- who are constitutionally protected from domestic spying -- are caught up in the NSA's surveillance dragnet.

Despite a promise from Obama's director of national intelligence James Clapper and a pledge by Coats, his successor, during his confirmation hearing earlier this year, neither administrations have confirmed how many Americans have had their data incidentally collected.

"The failure of the government to provide this information undermines effective Congressional oversight and the robust debate that this issue demands," said an ACLU statement.

Reversing his pledge, Coats said during Wednesday's hearing that the government will not release a number, citing a lack of resources and the risk of violating the privacy of those whose identities are verified.

Coats claimed that that were "no instances of intentional violations of Section 702" since the 2008 amended law introduced the statute.

Robyn Greene, policy counsel and government affairs lead at New America's Open Technology Institute, said in a tweet that there have, however, been cases of "unintentional systemic [and] persistent abuses," such as a recent case of the NSA having to end a controversial surveillance program that searched Americans' emails.

"That solution was ending the collection because the incident was so egregious," said Greene in a follow-up message.

National security blogger Marcy Wheeler too pointed out several instances of violations in a blog post, which she first published last year.

Congress is expected to vote on the reauthorization effort later this year before it expires on December 31.