EXCLUSIVE: Documents reviewed by Fox News show there are differences between Benghazi emails released through the federal courts to the conservative watchdog group Judicial Watch and emails released to the House oversight committee as part of its investigation into the attacks.

The discrepancies are fueling allegations the administration is holding back documents to Congress.

"The key question is whether Congress now has all the documents," Rep. Jason Chaffetz, R-Utah, a member of the oversight committee, said. As for differences between the two sets of documents, Chaffetz alleged: "They are playing games. The classification and redactions are different. Why should Judicial Watch get more than Congress after issuing a subpoena?"

The emails published by Judicial Watch last week, which showed additional White House involvement in shaping the public explanation of what happened, helped trigger the announcement Friday by House Speaker John Boehner of a select committee to investigate.

Two of the emails, from Sept. 14, 2012, appear to be part of the deliberations in advance of then-U.N. ambassador Susan Rice's Sunday show appearances were she linked an anti-Islam video to the Benghazi attacks. The emails released to Judicial Watch include the names of those who participated in the email chain.

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The same emails provided to the House committee do not include names.

While the text and subject line are redacted in full for both Judicial Watch and Capitol Hill, there are unexplained differences in the classification. The emails, originally marked "unclassified," were retroactively classified in February by the Department of State.

The email released to Judicial Watch is now marked "SECRET," and the same email released to the Oversight Committee is marked "Confidential." Both are marked to "DECLASSIFY" on Sept. 13, 2037 -- 25 years after the terrorist attack which killed four Americans.

Fox News also reviewed an email from Sept. 12, 2012 from Rice to members of the U.S. team at the United Nations where Rice was U.S. ambassador at the time. This unclassified email, whose subject line and text are also redacted in full, was retroactively classified on April 16, 2014, one day before it was released. While the contents and subject line were redacted in both versions, the email released as a result of the federal lawsuit to Judicial Watch does include the names, while the other does not.

Fox News does not have access to all the emails released to the House committee to assess whether this is part of a broader pattern. A spokesman for the oversight committee said they are still reviewing the 3,200 pages.

The spokesman said: "By withholding information, this Administration has only itself to blame for the continued questions about the before, during, and after of the Benghazi attacks. Removing information from documents subpoenaed by Congress, while the same documents with more information are released publicly, underscores the games the State Department continues to play as Congress presses for full and truthful answers about the deaths of four brave Americans."

When asked about reported differences in the released emails, White House spokesman Jay Carney said last week that the administration was forthcoming.

"We have, again, in a rather unprecedented way, provided documents that normally White Houses and administrations have not or would not provide because they were being mischaracterized," he said.

State Department spokeswoman Marie Harf said there was no effort to slow-walk the release of the emails.

"The notion that we are somehow deliberately doing any of that is just false. We've produced tens of thousands of documents. We've done nine hearings, 46 briefings. Everything we've seen come out in these document releases and on the Hill has underscored the exact same set of facts as we talked about yesterday about what happened in Benghazi and what happened since," Harf explained.