Michael Flynn, who recently resigned as President Trump’s national security adviser, has had his security clearance suspended by the Defense Intelligence Agency.

“General Flynn’s access to classified information was suspended pending a review,” a DIA spokesperson, James Kudla, told CBS News. The suspension took place Tuesday evening.

Flynn had maintained a security clearance since he was removed as head of the DIA on Aug. 7, 2014. His clearance could be reinstated in the future, pending the results of the review.

Flynn, a retired Army lieutenant general, was asked to resign by the Trump administration Monday evening. His departure followed reports that he had mislead administration officials, including Vice President Mike Pence, about a conversation he had in December with Russian ambassador Sergey Kislyak on the day the Obama administration announced retaliatory measures against Russia over its meddling in the U.S. elections.

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Flynn had originally said that he did not discuss U.S. sanctions on Russia during the call with Kislyak, although his spokesperson later said that Flynn could not recall whether sanctions had come up during the call.

On Wednesday, Mr. Trump defended Flynn, telling reporters at a press conference with Israeli Prime Minister Benjamin Netanyahu that the former national security advisor was a “wonderful man.”

“I think he’s been treated very, very unfairly by the media -- as I call it, the fake media, in many cases. And I think it’s really a sad thing that he was treated so badly,” Mr. Trump said.

Numerous Democrats have called for an investigation into Flynn and Mr. Trump’s relationship with the Russian government. On Wednesday, a number of top House Democrats sent a letter to White House counsel Donald McGahn requesting more information from the administration about Flynn amid reports that he was susceptible to Russian blackmail.

“Even in the face of strong warnings and evidence that he was vulnerable to being blackmailed, the White House appears to have considered General Flynn fit to continue serving as the National Security Advisor,” the Democrats wrote. “General Flynn continued to receive the nation’s most sensitive and classified information, without any apparent change to accommodate these national security concerns.”

CBS News Jeff Pegues and Howard Rosenberg contributed reporting to this story