US officials are working to establish the source of a leak of dozens of secret documents relating to the war in Ukraine.
The Pentagon has referred the matter to the Department of Justice, which has opened a criminal investigation.
Documents appeared on social media websites in early March.
According to Reuters, whose journalists have reviewed more than 50 of the documents, the intelligence purportedly revealed details of Ukrainian military vulnerabilities and information about allies.
The documents had not drawn much attention until a New York Times report on Friday, 7 April.