House Speaker Paul Ryan, R-Wis., on Wednesday formally urged Director of National Intelligence James Clapper to deny presumptive Democratic presidential nominee Hillary Clinton access to classified information – an appeal that comes as FBI Director James Comey is set to testify on the email probe which yielded no charges.

Ryan, in a letter to Clapper, said he wants Clinton prohibited from receiving classified information “for the duration of her candidacy for president.”

“There is no legal requirement for you to provide Secretary Clinton with classified information, and it would send the wrong signal to all those charged with safeguarding our nation’s secrets if you choose to provide her access to this information despite the FBI’s findings,” Ryan wrote.

Ryan said in his letter that if Clapper decides to deny his request, he would like him to explain why he would grant Clinton access to classified information despite the FBI’s findings that Clinton and her staff were “extremely careless in their handling of very sensitive, highly classified information.”

“I firmly believe this is necessary to reassure the public that our nation’s secrets are secure,” he adds.

His letter comes after Attorney General Loretta Lynch declared the investigation into Clinton's emails over with no criminal charges issued.

Ryan, a former vice presidential candidate, said in an interview with Fox News’ Megyn Kelly Tuesday that Clapper should “block” Clinton from receiving classified briefings after the Democratic National Convention.

He said on “The Kelly File” he received weekly CIA briefings as Mitt Romney's running mate in 2012 and said Clinton should not be given such information "given how recklessly she handled this."

"She grossly was negligent, she mishandled classified information and now she wants to be commander-in-chief," Ryan said in the interview.

Clinton spokesman Brian Fallon fired back, pressuring any Republicans joining what he called the “stunt” to say whether Donald Trump should have access to the same information.

Ryan also sent a letter to Comey requesting that he release all of the unclassified findings from the agency’s investigation into Clinton.

Comey is set to testify Thursday morning before the House Oversight and Government Reform Committee.

“Right now, there are simply too many unanswered questions,” Ryan wrote to Comey. “While we have started oversight hearings, as you stated earlier this week, ‘given the importance of the matter, I think unusual transparency is in order.’ I completely agree.

“The American people deserve to know exactly what your investigation uncovered and why the FBI came to the decision to recommend that no criminal charges be brought against Secretary Clinton.”

Meanwhile, the State Department is taking issue with at least one of the findings from the FBI investigation – that some of the emails on Clinton’s server had markings indicating classified information.

State Department spokesman John Kirby blamed “human error” for those markings, suggesting they shouldn’t have been there.

Fox News was first to report on a 2012 email that carried a classified code known as a “portion marking” when it was sent to Clinton’s account -- challenging her repeated claims that nothing she sent or received was marked classified at the time.

Fox News’ Chad Pergram contributed to this report.