The Ministry of Culture and Fine Arts has told Irish photographer Matt Loughrey to take down the photos of Khmer Rouge victims at Tuol Sleng Genocidal Museum which he allegedly colourised and altered to show them smiling.

The ministry said Loughrey's work is unacceptable, affecting the dignity of the victims, the reality of Cambodia's history and in violation of the rights of the museum as the lawful owner and custodian of the photographs.

The warning came after Loughrey had altered photos of several Khmer Rouge victims at the museum and published them through VICE website on April 9, entitled: "These People Were Arrested by the Khmer Rouge and Never Seen Again".

"The ministry requests that Matt Loughrey and Vice remove these images from their website. We urge researchers, artists and the public not to manipulate any historical sources, which is disrespectful of the victims.”

“The ministry will consider taking legal action, both through national and international channels, if Matt Loughrey does not honour the above request,” it said.

Loughrey and Vice have drawn public criticism for the move, with many demanding him to remove the photos.

An online petition has been launched for such purpose, with nearly 3,000 signing on it so far.

“VICE, take [the photos] down. Mr Loughrey, please stop using photos of Cambodian genocide victims for your experimentation and entertainment. We demand an apology,” said the petition on change.org.