US President Donald Trump on Friday reauthorised a controversial surveillance programme that allows the federal government to intercept and collect email and phone records of foreigners abroad without a warrant.

According to the Kuwait News Agency, KUNA, "Trump signed a renewal of Section 702 of the Foreign Intelligence Surveillance Act, FISA, after the Senate on Thursday voted 65 to 34 to approve a six-year extension of the most controversial foreign surveillance programme that allows the US government to collect communications from non-US citizens abroad without a warrant."

He defended the measure as a "critically important national security tool" for collecting intelligence on international terrorists, weapons proliferators and other important foreign intelligence targets located outside the US, the agency added.

"In order to detect and prevent attacks before they happen, we must be able to intercept the communications of foreign targets who are reasonably believed to possess foreign intelligence information, Trump said in a statement.

"Section 702 has proven to be among the Nation's most effective foreign intelligence tools. It has enabled our Intelligence Community to disrupt numerous plots against our citizens at home and our warfighters abroad, and it has unquestionably saved American lives," he added.

While the law targets foreigners, critics warn it has led to the incidental monitoring of millions of Americans who are communicating with non-US citizens outside the US. However, Trump defended the bill as constitutional, citing additional procedures to protect the privacy of Americans, KUNA concluded.