Deb Riechmann Associated Press

WASHINGTON – Some of the classified emails found on former Secretary of State Hillary Clinton’s home server were even more sensitive than top secret, according to an inspector general for the intelligence community.

Inspector General Charles McCullough sent a letter to lawmakers last Friday saying that several dozen additional classified emails have been found, including ones containing information from so-called “special access programs.” Intelligence officials say special access programs have a higher classification than top secret because they are about highly sensitive programs and could reveal sources of information.

The finding was first reported Tuesday by Fox News.

Federal investigators are probing the Democratic presidential candidate’s email setup amid concerns that classified information may have passed through the system.

Clinton provided the server to the FBI in August. She has said she didn’t send or receive information that was classified at the time via her personal email account.

McCullough sent the letter in response to inquiries from congressional committees about the classification methods used to review the Clinton emails. In responding to the request, McCullough said he sought sworn declarations from those involved in reviewing the emails.

“These declarations cover several dozen emails containing classified information determined … to be at the confidential, secret and top secret/sap levels,” according to the letter, which also was obtained by the Associated Press.

The Clinton campaign did not immediately respond to a request for comment.

The State Department is under court order to release the 55,000 emails that Clinton submitted to her former agency that were on her home-brew server and were not personal. Almost all have been released, with the last batch expected Jan. 29.

John Kirby, a spokesman for State, said the department is committed to releasing Clinton’s emails in a way that protects sensitive information. He said the Freedom of Information Act review process is still underway and said once it is complete, “if it is determined that information should be classified as top secret, we will do so.”