Ex-Khmer Rouge president Khieu Samphan is the latest member of Pol Pot's inner circle to be detained in Cambodia.

The French-educated guerrilla leader was led from a Phnom Penh hospital by police and taken to the UN-backed Killing Fields tribunal compound.

A panel of Cambodian and international judges are investigating one of the 20th century's darkest chapters.

During the Khmer Rouge four-year reign of terror, from 1975-79, an estimated 1.7 million people were executed, or died of torture, disease and starvation.

The tribunal said in a statement: "An initial appearance will be held today during which he will be informed of the charges which have been brought against him."

A close confidante of Pol Pot, the 78-year-old Khieu Samphan has denied knowledge of any atrocities committed by the Khmer Rouge.

Khieu Samphan is the fifth person to face the long-awaited Khmer Rouge tribunal, which began its work a few months ago after nearly a decade of delays caused by wrangling over jurisdiction and cash.

Former foreign minister Ieng Sary and his wife - both lifelong friends of Brother Number One Pol Pot - were arrested and charged last week with crimes against humanity.

Brother Number Two Nuon Chea, who had also lived in Pailin, is in the custody of the court on similar charges, as is the Khmer Rouge's chief jailer, Duch, who ran Phnom Penh's S-21 torture and interrogation centre.

Duch will be the first to make a public appearance at the tribunal when he appears for a bail hearing on Tuesday.

Khieu Samphan will be co-defended by the controversial French lawyer Jacques Verges, also known as the Terror Advocate, who knew Pol Pot in Paris in the early 1950s.

Mr Verges' previous clients include international guerrilla Carlos the Jackal and Nazi war criminal Klaus Barbie.

Pol Pot died in 1998 in the final Khmer Rouge redoubt of Anlong Veng.

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