The Pentagon said on Sunday that the US is examining the implications of an apparent leak of a number of highly classified information on national security, AFP reported on Monday.

The leak also has US officials scrambling to identify the leak's source, with some experts saying it could be an American rather than an ally, owing to the breadth of the topics addressed in the documents.

"The focus now is on this being a U.S. leak, as many of the documents were only in U.S. hands," Michael Mulroy, a former senior Pentagon official, told Reuters.

Last week, confidential documents were leaked online on platforms such as Discord, Telegram, and Twitter, with US national security secrets concerning China, Ukraine, and the Middle East - including sensitive intelligence reports, Ukraine war plans, and information on allies that the US obtained through spying on them.

This is seen as one of the most serious security breaches since more than 700,000 documents, videos, and diplomatic cables appeared on the WikiLeaks website in 2013.

One of the documents, dated February 23, was said to be labeled "Secret/NoForn" which meant that the content of the document was not meant to be disclosed to any foreign nation.

Classified documents leaked caused a reaction from the Pentagon. The #US admin is trying to persuade Twitter & Instagram to delete these documents relating to the #US plans in #Ukraine, deployment of forces, casualties of belligerents, supply of weapons & more v @Spriter99880 pic.twitter.com/JD6UMfNLrc

— Elijah J. Magnier 🇪🇺 (@ejmalrai) April 7, 2023

On her part, Deputy Pentagon Press Secretary Sabrina Singh confirmed that the documents "appear to contain sensitive and highly classified material."

"An interagency effort has been stood up, focused on assessing the impact these photographed documents could have on US national security and on our allies and partners," Singh added.

The Department of Justice, which is investigating the breach, stated last Saturday that is working closely with the Defense Department on the event.

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While senior US officials claimed that the documents were tampered with before being published, much of the information that was exposed is in accordance with CIA World Intelligence Review reports that are provided to the White House and Pentagon, the report said.

US officials considered that the leak of classified documents obscured US ties with key allies and partners as it undermined the US credibility and ability to keep secrets.

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