The memorandum comes as the White House spars with congressional Democrats over the work of Special Counsel Robert Mueller. Mueller led a two-year investigation into Russian interference in the 2016 US presidential election.
US President Donald Trump on May 23 ordered the intelligence community to cooperate with Attorney General William Barr's review of the events that prompted an investigation into links between the Trump campaign and Russia.
"Today, at the request and recommendation of the attorney general of the United States, President Donald J. Trump directed the intelligence community to quickly and fully cooperate with the attorney general's investigation into surveillance activities during the 2016 presidential election," White House spokeswoman Sarah Sanders said after Trump issued the directive.
The order also allows Barr to declassify any information he sees fit during his review.
The memorandum comes as the White House spars with congressional Democrats over the work of Special Counsel Robert Mueller. Mueller led a two-year investigation into whether Russia meddled in the 2016 US election and if there were any ties between the Trump campaign and Russia.
A redacted version of Mueller's report was released publicly in April. The probe found no evidence that the Trump campaign engaged in a criminal conspiracy with Russia and did not draw a conclusion on whether Trump obstructed justice, but outlined some incidents that congressional Democrats have said may be obstruction.
"Draining the Swamp"
Trump, a Republican, harbours suspicions that the Democratic Obama administration ordered him investigated during the 2016 campaign to try to undermine his candidacy, and he wants payback against those he believes were responsible.
"Comey, Brennan, Clapper, we're draining the swamp, folks," Trump told a rally on Monday in Pennsylvania, referring to former FBI Director James Comey, former CIA Director John Brennan, and James Clapper, a former director of national intelligence, all of whom have been critical of Trump.
Of specific interest to Trump are the warrants that emanated from a secretive court that authorises surveillance on foreign powers and their agents. Trump supporters believe the warrants will identify those responsible for the Russia probe that is still roiling Washington.
Last month, Barr said at a Senate hearing that "spying" on Trump's campaign was carried out by US intelligence agencies, though he later referred to his concerns as focused on "unauthorised surveillance."
Barr has assigned a top federal prosecutor in Connecticut to probe the origins of the Russia investigation in what is the third known inquiry into the opening of the FBI probe.