The Pentagon is demanding that the whistle-blower website WikiLeaks immediately return some 15,000 classified documents about the war in Afghanistan that it has not yet published.
Pentagon spokesman Geoff Morrell told reporters the website should "do the right thing" and return the thousands of documents.
Morrell said the Pentagon is pursuing other options if the website fails to comply, although he declined to answer a question about possible legal action.
Last month, WikiLeaks released some 91,000 government documents about Afghanistan, spanning 2004 to 2009 and detailing problems with the progress of the war.
Top Pentagon officials harshly criticized that release, saying the documents included the names of Afghans who were helping U.S. and allied troops. Officials said those Afghans could face reprisals from the Taliban.
WikiLeaks said it wants help from the Pentagon in removing names of Afghan sources in any future document releases.