Prosecutors in Cambodia are appealing against the 30-year jail sentence handed to a former Khmer Rouge prison chief, arguing it is too lenient.
Kaing Guek Eav, known as Comrade Duch, was found guilty by Cambodia's UN-backed war crimes court last month of war crimes and crimes against humanity for overseeing the mass murder of 15,000 men, women and children.
But international and Cambodian co-prosecutors believe his sentence gives insufficient weight to the gravity of his crimes, and undue weight was placed on mitigating circumstances.
The 67-year-old was the first Khmer Rouge leader to face an international tribunal, and the ruling was hailed as an historic day for Cambodia.