The Pentagon said on Sunday that an interagency task force is assessing the validity and impacts of "sensitive and highly classified material" that was leaked on various social media sites this week.

"Over the weekend, U.S. officials have engaged with Allies and partners and have informed relevant congressional committees of jurisdiction about the disclosure," Deputy Pentagon Press Secretary Sabrina Singh said in a statement. "The Department of Defense’s highest priority is the defense of our nation and our national security."

The leaked material, first reported by the New York Times on Friday, contains intelligence on China, the Middle East, Israel's spy agency Mossad, and U.S. support for Ukraine's military.

The Pentagon, which is the headquarters of the United States Department of Defense (DOD), is located in Arlington, Virginia. (STAFF/AFP via Getty Images)

Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, accused the Kremlin of doctoring the documents and leaking them to discredit U.S. support for the Ukrainian war effort.

"The fictitious "document" that ended up on the net most likely serves to discredit counter-offensive ideas and should provoke an increase in distrust between Ukraine and its partners or within Ukraine," Podolyak told Fox News.

UKRAINE WAR PLANNING DOCUMENTS LEAKED ONLINE, PENTAGON INVESTIGATING

Some inaccuracies on the documents, such as lower estimates for Russian troop deaths in Ukraine than what has been released publicly, have lead to skepticism about the authenticity of the material.

A Ukranian soldier stands atop an abandoned Russian tank near a village on the outskirts of Izyum, Kharkiv Region, eastern Ukraine, amid the Russian invasion of Ukraine. (JUAN BARRETO/AFP via Getty Images)

Ukrainian servicemen ride atop an armored fighting vehicle as Russia's attack on Ukraine continues at an unknown location in Eastern Ukraine. (Press service of the Ukrainian Ground Forces/Handout via REUTERS)

A member of the Ukrainian Territorial Defence Forces looks at destruction following a shelling in Ukraine's second-biggest city of Kharkiv. (SERGEY BOBOK/AFP via Getty Images)

One of the documents said that a Russia fighter jet nearly shot down a British reconnaissance plane off the Crimean coast last September, an event that could have drawn the U.S. and NATO into the war, according to the Washington Post. UK Defense Minister Ben Wallace previously told the British Parliament that the Russian jets flew "recklessly," but chalked the missile launch up to a "technical malfunction."

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The Department of Justice has opened a criminal investigation into the documents, which were photographed before being spread online.

The Associated Press contributed to this report.

Leak of 'highly classified material' is being assessed by interagency team, Pentagon says

Officials are investigating the validity of the classified material and how it ended up online