The Pentagon is investigating the alleged leak of classified U.S. documents about Ukraine’s war effort and military strength, a spokesperson confirmed on Friday.

These leaked documents purport to show sensitive information about the United States and NATO’s support for Ukraine’s fight against Russia.

Pentagon deputy press secretary Sabrina Singh did not comment on the documents’ authenticity but confirmed the Department of Defense is reviewing the situation.

“We are aware of the reports of social media posts, and the Department is reviewing the matter,” Singh wrote in an email on Friday.

The documents, which have circulated on Twitter and Telegram, are five weeks old.

One document labeled “top secret” purports to show the “Status of the Conflict as of 1 Mar.” Other documents offer insight into Ukraine’s troops and equipment.

As the New York Times reported:

Another document includes columns that list Ukrainian troop units, equipment and training, with schedules for January through April. The document contains a summary of 12 combat brigades that are being assembled, with nine of them apparently being trained and supplied by the United States and other NATO allies. Of those nine brigades, the documents said that six would be ready by March 31 and the rest by April 30. A Ukrainian brigade has about 4,000 to 5,000 soldiers, analysts said.

The leak comes as Kyiv is expected to launch a spring offensive against Russia.

Mykhailo Podolyak, one of Ukrainian President Volodymyr Zelensky’s top advisers, dismissed the leaked documents, calling them a “bluff” by Russia.

“If you have a working channel for receiving intelligence from the Pentagon, you will not destroy it just for a day of newsworthy headlines. If you have information about the level of support and military plans of the enemy, you will pretend that you do not have it,” Podolyak said in a Telegram post.

“If you try to pretend you know something, then you don’t know anything. This is a bluff, dust in the eyes,” he continued. “As for the real counteroffensive plans, the Russian troops will certainly be the first to get acquainted with them. I would assume that will happen very soon.”

One of the documents included discrepancies in the number of reported casualties, which is why some analysts suggest this portion of the document was doctored.

The New York Times reported:

For example, one of the slides said 16,000 to 17,500 Russian soldiers had been killed while Ukraine had suffered as many as 71,500 troop deaths. The Pentagon and other analysts have estimated that Russia has suffered far more casualties, with closer to 200,000 killed and injured, while Ukraine has had more than 100,000 killed and injured.

Still, former U.S. Ambassador to Russia John Sullivan told NBC the documents may “have some authenticity to them.”

“There are some indications that … there are some aspects of the document that have some authenticity to them, but there are also indications that this may be a Russian disinformation campaign, which they’re very good at,” Sullivan said.

Jordan Dixon-Hamilton is a reporter for Breitbart News. Write to him at jdixonhamilton@breitbart.com or follow him on Twitter.