The classified documents found in U.S. President Joe Biden's office during his vice president days were reported to contain intelligence briefings about Ukraine, Iran, and the U.K.

Some of the documents were marked as Top Secret or Sensitive Compartmented Information. The classified documents were found with other personal documents from Biden's Center for Diplomacy at the University of Pennsylvania in Washington.

Some of the personal documents that were mixed with the classified documents include planning materials for the funeral of the president's son, Beau Biden, in 2015.

The classified documents were dated between 2013 and 2016, according to one source with knowledge of the matter.

The materials were found on November 2, just almost a week before the midterm elections. However, it only came to public attention on Monday.

The source noted that a personal lawyer for the U.S. president was closing out the downtown D.C. office that was used as part of his teaching work at the University of Pennsylvania.

The personal lawyer reportedly opened a manila folder that was labeled "personal" and noticed that there were classified documents inside.

The same personal familiar with the matter noted that the lawyer then called the National Archives upon seeing the envelope.

Biden's team then turned over several boxes in an abundance of caution. Several of those boxes include personal materials.

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U.S. President Joe Biden's Classified Documents

 The White House said in a statement that the president's personal lawyers have cooperated with the Archives and the Justice Department since the discovery of the classified documents.

The Biden administration also clarified that the materials were not the subject of any previous request or inquiry by the archives.

Biden also commented on the recent discovery of the documents saying that he does not know what the documents contained.

The president added that his lawyers have not suggested that he asks what the documents were about.

The Justice Department refused to comment on the Biden classified documents. Meanwhile, Chicago U.S. Attorney John Lausch Jr. was tapped to review the materials. His office also declined to comment on the matter.

One person with knowledge of the probe noted that the initial review of the Chicago U.S. attorney is nearing completion.

Classified Documents

Biden has earlier criticized former U.S. President Donald Trump, dubbing him as "irresponsible" for having classified documents at Mar-a-Lago.

Trump is currently under criminal investigation over allegations regarding how he mishandled classified documents that were removed from the White House.

The revelation has prompted others to draw a comparison between Biden's and Trump's classified documents.

The former president has also refused to return more than 11,000 administration documents despite repeated requests from the Archives under Presidential Records Act.

One Trump lawyer also signed a statement that all classified records had been returned before the August search of his residence.

On the other hand, Biden voluntarily returned the 10 classified documents to the Archives the day they were discovered.

A national security lawyer, Brad Moss, noted that the Biden staff did what they were supposed to do by notifying Archives and returning the documents.

GOP Kentucky congressman James Comer said in a statement that they expect the same treatment for Biden.

Trump also posted on his Truth Social account asking when the Federal Bureau of Investigation will raid the "many homes" of Biden.

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This article is owned by Latin Post.

Written by: Mary Webber

WATCH: Pres. Joe Biden addresses discovery of classified documents in former office - from CNBC Television