Phnom Penh (dpa) - The legal team that successfully prosecuted the Khmer Rouge‘s former security chief said Tuesday that it was appealing for his sentence to be lengthened.

   Prosecutor Andrew Cayley said he was asking the international war crimes tribunal to extend Comrade Duch‘s sentence to life in prison from the 30 years it gave him in July after he was convicted of war crimes and crimes against humanity.

   A life sentence for Duch, 67, would be "fundamental" and would serve as a symbol for his crimes, Cayley said.

   "We believe it should be life imprisonment for those types of crimes," Cayley told the German Press Agency dpa.

   Duch, whose real name is Kaing Guek Eav, headed the Khmer Rouge‘s torture and execution centre in Phnom Penh known as S-21, where at least 14,000 people were tortured and executed during the Maoist movement‘s rule of Cambodia from 1975 to 1979.

   Cayley said, however, that the prosecution would accept reductions in a life sentence. He said it would be satisfied if it were commuted to 45 years in recognition of Duch‘s illegal detention prior to trial.

   Duch was arrested in 1999 and held until he went on trial before the UN-backed war crimes tribunal in 2009. Under Cambodian law, defendants may not be held for more than three years without trial, consequently entitling Duch to a reduction of sentence.

   The prosecution would also accept another deduction of at most five years from the term for "very limited" mitigating factors, such as cooperation and expressions of remorse, Cayley said.

   "This man was a willing participant in [the crimes] for three and a half years," he said. "We are talking about more than 10,000 people dead. There is not a lot you can say in mitigation."

   The final sentence levied by the appeal court would be reduced by a further 11 years for the time Duch has already spent behind bars.  

   The tribunal sentenced the defendant to 30 years, but with deductions for time served, Duch would serve just 19 more years. Many Cambodians felt that term was too lenient.

   In August, Duch‘s defence team appealed the verdict, saying the court should acquit him and describing his conviction as "a miscarriage of justice."

   The appeal hearing would likely take place early next year for Duch, the first defendant to be tried by the tribunal.

   Four other former Khmer Rouge leaders currently in detention were charged last month for their alleged involvement in the deaths of 1.7 million people from execution, disease, starvation and overwork.

   The four ex-leaders, whose trials are expected to start next year, are: Brother Number Two Nuon Chea, the movement‘s ideologue; head of state Khieu Samphan; foreign minister Ieng Sary; and his wife, former social affairs minister Ieng Thirith.

   The movement‘s leader, Pol Pot, died in 1998.