WASHINGTON — Intelligence professionals warned Friday that President Donald Trump’s decision to give his loyal attorney general carte blanche to disclose still-secret material from the Russia investigation will let William Barr cherry-pick intelligence to paint a misleading picture about what started the probe.

The president claims his campaign was spied upon, though Trump administration officials have said they have no specific evidence that anything illegal was done when the campaign came under FBI surveillance approved by a court.

On Thursday, Trump gave Barr full authority to publicly disclose information about the origins of the investigation that the president repeatedly has dismissed as a “hoax.”

“You have to get down to what happened because what happened is a tremendous blight on our country,” Trump said, adding that Barr is highly respected and will be impartial in reviewing documents.

But Trump’s critics are wary of leaving the decision of what intelligence to release — and what should remain hidden — in Barr’s hands. Barr is a staunch Trump defender who, Democrats say, spun special counsel Robert Mueller’s report in Trump’s favor, playing down aspects suggesting possible criminal conduct. Mueller has also complained to Barr about his handling of the release of the report.

That has prompted concern that Barr will take a similar approach to his review of the origins of Mueller’s probe, releasing intelligence backing Trump’s claims that it was politically motivated, while keeping evidence demonstrating the need for the probe classified.

Barr already has said he believes “spying did occur” on the Trump campaign, but he also made clear at a Senate hearing that any surveillance wasn’t necessarily illegal or improper.

Barr has asked the U.S. attorney in Connecticut to examine the origins of the Russia investigation to find out whether intelligence and surveillance methods used during the probe were lawful and appropriate.

Traditionally, when Congress, for instance, asks for material to be declassified, the request is forwarded to the intelligence agencies where the information originated or resides. Those agencies recommend what part, if any, can be declassified without jeopardizing intelligence sources or spy craft. Then, the office of the director of national intelligence coordinates the feedback from all the agencies and makes a decision.

National Intelligence Director Dan Coats said in a statement Friday that 17 intelligence agencies he represents will provide the Justice Department all appropriate information needed for its review of intelligence activities related to Russian interference in the 2016 presidential election.

While Trump’s memorandum instructs Barr to consult with appropriate intelligence agencies “to the extent he deems it practicable” before he releases anything, it doesn’t require him to do so. This has alarmed Trump critics who have served in high-level U.S. intelligence posts.

“It is potentially dangerous if the attorney general were to declassify something the director of national intelligence thought should be kept classified, as the director is in the best position to judge the damage to intelligence sources and methods,” said Michael Morell, a former U.S. intelligence official and host of the Intelligence Matters podcast.

Morell said Trump should never have given Barr the declassification authority. “It is yet another step that will raise questions among our allies and partners about whether to share sensitive intelligence with us,” he said.

David Kris, former head of the Justice Department’s national security division, said it’s “very unusual — unprecedented in my experience — for a nonintelligence officer to be given absolute declassification authority over the intelligence.” Kris said people expect the nation’s top law enforcement officer to be nonpartisan and there is now fear the apolitical nature of intelligence could be threatened.