People using CIA and FBI computers have edited entries in the online encyclopedia Wikipedia on topics including the Iraq war and the Guantanamo prison, according to a new tracing programme.

The changes may violate Wikipedia's conflict-of-interest guidelines, a spokeswoman for the site said.

The programme, WikiScanner, was developed by Virgil Griffith of the Santa Fe Institute in New Mexico and posted this month on a website that was quickly overwhelmed with searches.

The programme allows users to track the source of computers used to make changes to the popular internet encyclopedia where anyone can submit and edit entries.

WikiScanner can be found at http://wikiscanner.virgil.gr/

The programme revealed that CIA computers were used to edit an entry on the US-led invasion of Iraq in 2003. A graphic on casualties was edited to add that many figures were estimated and were not broken down by class.

Another entry on former CIA chief William Colby was edited by CIA computers to expand his career history and discuss the merits of a Vietnam War rural pacification programme that he headed.

Aerial and satellite images of the US prison for terrorism suspects at Guantanamo Bay, Cuba, were removed using a computer traced to the FBI, WikiScanner showed.

CIA spokesman George Little said he could not confirm whether CIA computers were used in the changes, adding that "the agency always expects its computer systems to be used responsibly."

The FBI did not have an immediate response.

Computers at numerous other organisations and companies were found to have been involved in editing articles related to them.

Griffith said he developed WikiScanner "to create minor public relations disasters for companies and organisations I dislike (and) to see what 'interesting organisations' (which I am neutral towards) are up to."

It violates Wikipedia's neutrality guidelines for a person with close ties to an issue to contribute to an entry about it, said spokesman Sandy Ordonez of the Wikimedia Foundation, Wikipedia's parent organisation.

However, she said, "Wikipedia is self-correcting," meaning misleading entries can be quickly revised by another editor. She said Wikimedia welcomed the WikiScanner.

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