The Justice Department will prosecute anyone found to have violated U.S. law in the leaks of classified government documents by online whistleblower WikiLeaks, Attorney General Eric Holder said Monday.

"This is not saber-rattling," said the attorney general, who declared that the Obama administration condemns the leaks.

Holder said the latest disclosure, involving classified State Department documents, puts at risk the security of the nation, its diplomats, intelligence assets and U.S. relationships with foreign governments.

"To the extent that we can find anybody who was involved in the breaking of American law, who put at risk the assets and the people I have described, they will be held responsible; they will be held accountable," Holder said at a news conference on another topic. He called the WikiLeaks probe "an active, ongoing criminal investigation."