The Justice Department has launched a criminal investigation into an apparent leak of Pentagon documents revealing details about the U.S. role in the Ukraine war, and Russian operations in Ukraine and beyond. They include data on U.S. surveillance drones in the region and ammunition needed by Ukrainian forces.

The materials also contain information about China and reveal U.S. intelligence gathering on allies including Ukraine, South Korea and Israel. The documents date from late February to early March but have appeared on social media in recent weeks, including last Friday.