A photo of Bin Laden from 1998 (left) was digitally altered using elements from an image of Gaspar Llamazares (right)
A Spanish politician has said he was shocked to find out the FBI had used his photo for a digitally-altered image showing how Osama Bin Laden might look.
Gaspar Llamazares said he would no longer feel safe travelling to the US after his hair and parts of his face appeared on a most-wanted poster.
He said the use of a real person for the mocked-up image was "shameless".
The FBI admitted a forensic artist had obtained certain facial features "from a photograph he found on the internet".
The digitally-altered photos of the al-Qaeda leader, showing how he might look now, aged 52, were published on the state department's Rewards for Justice website on Friday.
Officials said they had adapted a 1998 file image to take account of a decade's worth of ageing, and possible changes to facial hair.
'Unintentional and inadvertent'
Mr Llamazares, 52, the former leader of the United Left coalition in parliament, said he could not believe it when he was first told about the similarity between himself and the new photo-fit of Bin Laden.
He said he soon realised that his forehead, hair and jaw-line had been "cut and pasted" from an old campaign photograph.
"I was surprised and angered because it's the most shameless use of a real person to make up the image of a terrorist," he told a news conference.
"It's almost like out of a comedy if it didn't deal with matters as serious as Bin Laden and citizens' security."
The FBI claimed to have used "cutting edge" technology, but Mr Llamazares said it showed the "low level" of US intelligence services and could cause problems if he was wrongly identified as the Saudi.
"Bin Laden's safety is not threatened by this but mine certainly is," he said, adding that he was considering taking legal action.
Later, an FBI spokesman told the BBC that it was "aware of the similarities in hairline features of the age-progressed photograph of Osama Bin Laden, posted on the web yesterday, and that of an existing photograph of a Spanish public official".
"When producing age-progressed photographs, forensic artists typically select features from a database of stock reference photographs to create the new image."
"After a preliminary review, it appears that in this instance the forensic artist was unable to find suitable features among the reference photographs and obtained those features, in part, from a photograph he found on the internet."
"The forensic artist was not aware of the identity of the individual depicted in the photograph. The similarities between the photos were unintentional and inadvertent."