Attorney General Eric Holder has revealed the U.S. Justice Department has launched a criminal investigation into the whistleblowing website WikiLeaks, which this week began publishing more than 250,000 secret U.S. diplomatic cables.

Eric Holder: “Along with other members of the administration, I condemn the action that WikiLeaks has taken. It puts at risk our national security, but in a more concrete way, it puts at risk individuals who are serving this country in a variety of capacities, either as diplomats, as intelligence assets, puts at risks the relationships that we have with important allies around the world. We have an active, ongoing criminal investigation with regard to this matter. We are not in a position, as yet, to announce the result of that investigation, but the investigation is ongoing.”

The Washington Post reports federal authorities are investigating whether WikiLeaks founder Julian Assange could be charged under the Espionage Act of 1917. Meanwhile, Assange says he plans to continue publishing secret documents. Assange told Forbes Magazine that WikiLeaks is preparing a massive leak of documents from a big U.S. bank early next year.