Police in Cambodia have entered the house of the former Khmer Rouge Foreign Minister Ieng Sary.
Police and officials from Cambodia's UN-backed genocide tribunal have taken former Khmer Rouge Foreign Minister Ieng Sary into custody.
It is thought he will be arrested and taken to face trial at Cambodia's UN-backed genocide tribunal.
The former leader was detained after police surrounded his home in Phnom Penh early in the morning.
Ieng Sary is Pol Pot's brother-in-law. He became the first senior Khmer Rouge leader to defect in 1996 - and as a result was granted a royal pardon.
He will be taken before judges who will decide if he should face charges.
However, he is believed to be under investigation for crimes committed under the 1970s regime.
Ieng Sary was the brother-in-law of Khmer Rouge leader Pol Pot. Some one million people are thought to have died under the Khmer Rouge's 1975-1979 rule.
He has repeatedly denied responsibility for any crime.
The former foreign minister is the third senior official to be targeted by the tribunal.
The United Nations says a royal pardon cannot protect someone from prosecution.
Former Khmer Rouge second-in command Nuon Chea and former prison chief Kang Kek Ieu - also known as Duch - have both been charged with crimes against humanity.
Roads around Ieng Sary's luxury villa in the capital Phnom Penh have been sealed off by military police.
Tribunal officials were seen entering the house, which Ieng Sary shares with his wife, Ieng Thirith, who served as the Khmer Rouge social affairs minister.
She is also likely to be arrested.
The BBC's Guy DeLauney in Phnom Penh says police and officials are currently searching the house, which they have to do in the presence of those being charged.
Torture and executions
Prosecutors for the tribunal have said there is evidence of Ieng Sary's participation in crimes, including planning, directing and coordinating forced labour and unlawful killings.
During the Khmer Rouge's 1975-79 rule, Ieng Sary convinced many educated Cambodians who had fled the country to return.
Many were then tortured and executed as part of the purge of intellectuals, some of them diplomats from his own office.
Ieng Sary is said to be ill with a heart condition, and travels to Bangkok regularly for treatment.
Pol Pot, the founder and leader of the Khmer Rouge, died in a camp along the border with Thailand in 1998.
His deputy Nuon Chea and Kang Kek Ieu, or Duch, head of the notorious Tuol Sleng prison, have already been arrested by the tribunal to face charges of war crimes and crimes against humanity.
The court got under way last year after a decade of negotiations between the UN and the Cambodian government. Trials are expected to start in 2008.
As many as two million people are thought to have died during the four years of Khmer Rouge rule, but no-one has ever been prosecuted.
