WASHINGTON, United States (AFP) — The US House of Representatives passed a crucial surveillance law Thursday that reinforced the ability of the country’s spy agencies to intercept and make use of Americans’ private communications.

The national security establishment saw the reauthorisation of the expiring Section 702 of the Foreign Intelligence Surveillance Act as essential, warning that they would not be able to detect terror plots without it.

But rights groups and libertarian-leaning politicians of both the Democratic and Republican parties saw the bill’s passage as a blow, especially since former National Security Agency contractor Edward Snowden revealed in 2013 that the NSA was using it to vacuum up massive amounts of data on Americans.

Many had hoped the renewal would strengthen protections against invasive electronic wiretapping and social media monitoring of Americans by the NSA, the country’s powerful electronic espionage body, and the Federal Bureau of Investigation.

The House’s vote for the bill came after President Trump himself sent mixed messages of his own views, tweeting Thursday morning his opposition only to make an abrupt U-turn.

In an initial tweet he said the section 702 provision had been used by the Obama administration to “so badly surveil and abuse the Trump campaign,” suggesting he was opposed to the bill.

More than an hour later, he reversed himself, saying “today’s vote is about foreign surveillance of foreign bad guys on foreign land. We need it!”

While nearly all lawmakers agree that 702 is an essential tool for US intelligence to safeguard national security, the bill passed the House by 256-164, showing the level of opposition to the powers it gives US spies and law enforcement. The no votes included 45 Republicans.

“The House-passed bill does absolutely nothing to defend the vast majority of law-abiding Americans from warrantless searches, and in many ways it expands the federal government’s ability to spy on Americans. A concerted campaign of fear-mongering and misinformation pushed this flawed bill over the line,” said Senator Ron Wyden, one of the most vocal critics of the law.

Section 702 of the FISA law was passed in 2008 after the Bush administration was shown to have allowed the then-illegal surveillance of telephone and online communications of US citizens and residents in the wake of the September 11, 2001 terror attacks.

Amid concerns it gave the government too much power to spy on citizens, the statute was given a five-year limit, and was renewed in 2012.

It allows the NSA and FBI, in their surveillance on foreign targets outside of the country for national security purposes, to also collect and hold communications by US citizens, so-called incidental collection.

It also permits the CIA and FBI to search that material, which includes social media postings, in the course of criminal investigations.

The NSA and FBI have downplayed their collection and use of the materials on Americans.

But leaks and statements by officials have suggested that the amount of material collected is massive, and that the FBI routinely searches it for information on Americans.

Opponents had hoped the new bill would require agencies to obtain specific warrants to scan and make use of the communications of Americans scooped up in the process of spying on foreigners. But a slight change that says the FBI needs a warrant to make use of the material in court does not hinder their ability to freely examine NSA files, critics said.

The bill “fails to meaningfully restrict the use of Section 702 to spy on Americans without a warrant,” the American Civil Liberties Union said.

The bill could face stronger opposition in the Senate, where Senator Rand Paul has threatened a filibuster. But analysts expect that will only slow its eventual passage.