WikiLeaks founder Julian Assange said the whistleblower website planned to release more secret Afghan war documents regardless the Pentagon's warning to withhold the material, according to media reports.

Assange said Thursday via video link to an audience in London that the site was preparing to release the final 15,000 classified files, the remaining documents from a huge cache which were published last month, AFP reported.

The Pentagon said it believes it has identified the additional 15,000 classified documents, and said that the leak would put U.S. troops and Afghan informers at risk.

The extraordinary disclosure laid bare classified military documents covering the war in Afghanistan from 2004 to 2010. It exposed unreported incidents of Afghan civilian killings by NATO forces and covert operations against Taliban figures.

The documents also included the names of some Afghan informants, prompting claims that the leaks have endangered lives.

In a statement Thursday, Pentagon spokesman Geoff Morrell said the "only responsible course of action for them is to immediately remove all the stolen documents from their website and expunge all classified material from their computers."

"If they were to publish any additional documents after hearing our concerns about the harm it will cause our forces, our allies and innocent Afghan civilians it would be the height of irresponsibility. It would compound a mistake that has already put far too many lives at risk," Morrell was quoted by the Reuters as saying.

WikiLeaks caused an uproar when it published more than 70,000 documents last month.