The whistleblower website Wikileaks is expected to release hundreds of thousands of secret military files.

It is understood Wikileaks is preparing to release as many as 400,000 sensitive intelligence files relating to the US-led war in Iraq.

The files have been leaked to the whistleblower website from an unconfirmed source.

The Pentagon has begun scouring through its own Iraq war databases to prepare for the fallout and has reportedly set up a 120-person taskforce to assess the possible impact.

The release, if it goes ahead, would eclipse the recent publication of more than 70,000 classified US military files on the war in Afghanistan, which caused an outcry in Washington.

The US has urged Wikileaks to return the new documents to the US military.