WASHINGTON (Reuters) - The Pentagon urged news organizations on Monday not to publish classified U.S. documents due to be released by WikiLeaks as U.S. officials brace for a mass disclosure of leaked Iraq war files by the whistle-blower website.

U.S. soldiers of the 1st Battalion, 116th Infantry Regiment, wait to load their luggage as they prepare to pull out from Iraq and leave for Kuwait from Tallil Air Base near Nassiriya, 300 km (185 miles) southeast of Baghdad, August 15, 2010. REUTERS/Thaier al-Sudani

WikiLeaks, which in July released some 70,000 U.S. documents on the Afghanistan war, is expected soon to post on its website as many as 500,000 classified leaked U.S. documents from the Iraq war. The U.S. government in July condemned the release of the initial leaked documents, which painted a grim picture of the war in Afghanistan that began in 2001.

Pentagon spokesman Colonel David Lapan said the U.S. military is “absolutely” urging WikiLeaks to “return the stolen documents to the United States government and ... not publish them.” Lapan also appealed to the news media.

“News organizations should be cautioned not to facilitate the leaking of classified documents with this disreputable organization known as WikiLeaks,” Lapan said.

“The concern is that WikiLeaks as an organization should not be made more credible by having credible news organizations facilitate what they’re doing,” he said.

The Pentagon’s comments came on the same day that Sweden said it denied a work and residency permit to Julian Assange, founder of WikiLeaks.

Assange has been establishing a base in Sweden in order to benefit from the Nordic country’s strict journalist protection laws. He is also being investigated over rape allegations in Sweden, which he has denied, calling them baseless.

Assange, an Australian citizen, can appeal the decision within three weeks.

‘VENEER OF LEGITIMACY’

At the Pentagon, Lapan said he was not suggesting that news organizations ignore leaked documents, but questioned providing “a veneer of legitimacy to WikiLeaks” by publishing the originals.

“WikiLeaks as an organization is irresponsible in taking hundreds of thousands, potentially in this case, at least tens of thousands in past instances, of classified stolen documents and publishing them on the Web,” Lapan said.

A Pentagon team already has reviewed the set of documents that it believes WikiLeaks is preparing to publish, Lapan said. The 120-member team is prepared to move quickly once the documents are published to verify whether they are the same and to assess the damage they might cause, he said.

With the early review, the Pentagon hopes to be able to move rapidly to mitigate any damage the leaks might cause to their intelligence sources and methods of operations, Lapan said. A main concern is for the safety of Iraqis named in the files who may have assisted U.S. forces, he said.

The documents posted by WikiLeaks in July detailed allegations that U.S. forces sought to cover up civilian deaths as well as U.S. concern that Pakistan secretly aided Taliban militants even as it took billions of dollars in U.S. aid.

At the time of the July leak of Afghanistan war documents, the top U.S. military officer, Admiral Mike Mullen, said that WikiLeaks might have the blood of U.S. troops and Afghan civilians on its hands because it had leaked files naming people who had collaborated with U.S. forces.

But U.S. Defense Secretary Robert Gates said in an August 16 letter to the head of the Senate Armed Services Committee that the leak had not revealed any “sensitive intelligence sources or methods.”