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. 

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. 

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."

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.