A controversial US law which allows warrantless internet surveillance is set to be reauthorised by Donald Trump.

On Thursday, the US Senate passed a bill to renew Section 702 of the Foreign Intelligence Surveillance Act (FISA) which allows American authorities to conduct mass surveillance on foreign targets on US soil.

It now needs to be signed off by the President, who initially suggested he would oppose it on Twitter before quickly retracting his stance in what critics described as a "humiliating backpedal".

When the bill was before the House of Representatives, the lower chamber of the US legislature, Mr Trump tweeted: "This is the act that may have been used, with the help of the discredited and phony dossier, to so badly surveil and abuse the Trump Campaign by the previous administration and others?"

“House votes on controversial FISA ACT today.” This is the act that may have been used, with the help of the discredited and phony Dossier, to so badly surveil and abuse the Trump Campaign by the previous administration and others? — Donald J. Trump (@realDonaldTrump) January 11, 2018

Last year, British intelligence agency GCHQ made a rare public statement to dismiss "utterly ridiculous" claims by the President that it was used by the Obama administration to tap his wires before the election.


Image: GCHQ denied Trump's claims in a rare statement

Almost two hours after his first tweet, he wrote: "With that being said, I have personally directed the fix to the unmasking process since taking office and today's vote is about foreign surveillance of foreign bad guys on foreign land. We need it! Get smart!"

With that being said, I have personally directed the fix to the unmasking process since taking office and today’s vote is about foreign surveillance of foreign bad guys on foreign land. We need it! Get smart! — Donald J. Trump (@realDonaldTrump) January 11, 2018

Matt Tait, a former GCHQ worker and frequent critic of President Trump, described the post as a "humiliating backpedal".

Its approval is widely supported by the intelligence community who consider its powers vital, but it is opposed by privacy campaigners and civil liberties groups.

Libertarian Republicans and liberal Democrats had pushed for it to be reformed following the global surveillance revelations provided by whistleblower Edward Snowden.

It will need to be reauthorised again in six years' time.