PHNOM PENH: Cambodia condemned images published by U.S. media group VICE featuring newly colourised photographs of the Khmer Rouge "killing fields" victims, saying the images were an insult to the dead because some mugshots had been altered to add smiles.

VICE removed the article and photos later on Sunday, saying they did not meet its editorial standards and it was investigating.

The artist behind the work, Matt Loughrey, declined to comment.

In the article published on Friday, Loughrey said his project to colourise images from the notorious Tuol Sleng prison, or S-21, aimed to humanise the 14,000 Cambodians executed and tortured there.

However, the article caused a backlash on social media after comparisons with the original black-and-white photos showed that some subjects were smiling only in Loughrey's colour images. The VICE article did not contain the original images.

"To play around by using technology to put make-up on the victims of S21... is a very grave insult to the souls of the victims of #genocide," exiled Cambodian politician Mu Sochua wrote on Twitter.

Cambodia's Ministry of Culture had issued a statement calling on VICE to remove the images.

"We urge researchers, artists and the public not to manipulate any historical source to respect the victims," the ministry said.

Loughrey, who in the VICE interview said he had worked with victims' families to restore the photos, declined to comment when contacted by Reuters.

VICE removed the article late on Sunday, and on Monday issued a statement.

"The article included photographs of Khmer Rouge victims that Loughrey manipulated beyond colorisation," the statement said, adding they did not meet its editorial standards. "We regret the error and will investigate how this failure of the editorial process occurred."

At least 1.7 million Cambodians died in the extremist Khmer Rouge’s reign of terror in Cambodia from 1975 to 1979.