The Washington Post reported that Hegseth had issued an order for all officers ranked one-star and above who are serving in command positions to gather for a meeting -- along with their top enlisted advisors -- at the Quantico military base in Virginia on Tuesday.

When asked about the report, the Pentagon replied with a statement from spokesman Sean Parnell that said Hegseth "will be addressing his senior military leaders early next week," without providing an explanation or further details.

Hegseth's order -- which affects officers deployed around the world as well as those in the United States -- is highly unusual.

"People are very concerned. They have no idea what it means," the Post quoted one person as saying.

CNN meanwhile quoted US officials as saying that hundreds of generals and admirals had been called to attend the meeting.

In May, Hegseth ordered major cuts to the number of general and flag officers in the US military, but it was unclear if the meeting next week was related to that directive.

The Pentagon has seen a series of major shakeups this year under President Donald Trump's administration, which has fired several of the country's most senior officers, usually without providing an explanation.