The Pentagon has said it would not negotiate for a "sanitised" release of thousands of sensitive Afghan war documents, currently in possession of whistleblower website WikiLeaks that has plans to make them public.

The Defence Department however acknowledged that an attempt was made to contact the lawyer of the website.

WikiLeaks, which has already released a huge cache of classified documents on the Afghan war, is still in possession of 15,000 documents which it plans to upload soon.

"We are not interested in negotiating any sort of minimisation or sanitised version of classified documents," Pentagon spokesman Bryan Whitman told reporters when asked about the offer made by WikiLeaks to review the documents, before they are made public.

The Department of Defense has not changed its position on documents, he said.

"Our position has been consistent and clear, and that is that these documents should be returned, there should be no further posting of these classified documents. And that those that have been posted should be removed," Whitman said.

A similar demand was made by Jeh Charles Johnson, General Counsel, Department of Defense, in a letter to Timothy Matusheski, who represents himself as WikiLeaks attorney.

"The Department demands that nothing further be released by WikiLeaks, that all of the classified documents that WikiLeaks has obtained be returned immediately, and that WikiLeaks remove and destroy all of these records from its databases," said the letter dated August 16.

According to the letter there was a phone call scheduled between Johnson and Matusheski, but the latter was a "no-show for the call".

WikiLeaks founder Julian Assange has said that the Pentagon has expressed willingness to discuss a request for help in reviewing classified documents from the Afghan war and removing information that could harm civilians.

In his letter Johnson says that WikiLeaks is holding the property of the US Government, including classified documents and sensitive national security information, that has not been authorised for release.

It said the circumstances in which the material was obtained constitute a violation of US law.

"The Secretary of Defense has made clear the damage to our national security by the public release by WikiLeaks of some 76,000 classified documents several weeks ago, and the treat to the lives of coalition forces in Afghanistan and to the lives of local Afghan nationals as a result," it said.

"As the Secretary has also stated, we know from various sources that our enemies are accessing the WikiLeaks website for the purpose of exploiting WikiLeaks' illegal an irresponsible actions, to pursue their own terrorist aims," it said.