Nuon Chea, the top surviving leader of Cambodia's notorious Khmer Rouge, whose radical policies were responsible for the deaths of an estimated 1.7 million people, was charged Wednesday with crimes against humanity and war crimes.

Nuon Chea was arrested early Wednesday morning at his home in Pailin in northwestern Cambodia near the Thai border and flown to the Cambodian capital Phnom Penh, where he was put in the custody of a U.N.-supported genocide tribunal.

The tribunal is investigating abuses committed when the communist Khmer Rouge held power in 1975-79. The Khmer Rouge have been blamed for the deaths of their countrymen from starvation, ill health, overwork and execution.

A statement released by the Extraordinary Chambers in the Courts of Cambodia — the formal name by which the tribunal is known — said Nuon Chea had been placed in "provisional detention."

Police surrounded his home in Pailin in northwestern Cambodia near the Thai border and served him with an arrest warrant. Police Capt. Sem Sophal said he was being arrested on charges of crimes against humanity, but did not show a copy of the warrant to reporters.

Officers later took the 82-year-old Nuon Chea — who denies any wrongdoing — into custody and put him into a car and then a helicopter for the capital, Phnom Penh, as his son and dozens of onlookers gathered to watch the historic scene in silence, witnesses said.

"My father is happy to shed light on the Khmer Rouge regime for the world and people to understand," Nuon Say said afterward.

Nuon Say said his mother fainted after seeing her husband taken away by police. He said Nuon Chea rolled down the window of the car and took one last look at his son, and said nothing.

In Phnom Penh, a convoy transported Nuon Chea from a military airport in the capital to the offices of the tribunal.

"Now the time has come for him to share his version of the history of Khmer Rouge before the court of law," Youk Chhang, director of the Documentation Center of Cambodia, an independent group researching Khmer Rouge crimes, said Wednesday.

"So many people have died. The facts are everywhere. There are plenty of mass graves, prisons, documents, photographs that can show what he did at that time," Youk Chhang said.

Nuon Chea joined the Khmer Rouge in the 1950s in its formative stages as the country's underground communist party, later becoming its chief political ideologue.

Prosecutors for the U.N.-backed genocide tribunal have said there are five senior Khmer Rouge figures they have recommended for trial in connection with the group's policies causing people's deaths through hunger, illnesses, overwork and execution. Nuon Chea is the second, and highest-ranking, Khmer Rouge leader detained to appear before the panel.

Kaing Guek Eav, commonly known as Duch who headed the former Khmer Rouge S-21 prison, was the first suspect detained by the tribunal on charges of crimes against humanity. He was charged last month. The other suspects have not been publicly named.

Nuon Chea, considered the right-hand man to Pol Pot, has consistently denied any responsibility for the regime's mass brutality, though he said in an interview with the AP last month that he was ready to face the tribunal.

"I was president of the National Assembly and had nothing to do with the operation of the government," he said in the interview. "Sometimes I didn't know what they were doing because I was in the assembly."

Theary Seng, the director of Center for Social Development, a nonprofit group monitoring development of the Khmer Rouge tribunal, said Nuon Chea's arrest was "a very good starting point."

"Even if we don't see a conviction, at least we have witnessed a process" of searching for justice, Theary Seng said.

The late Khmer Rouge leader Pol Pot died in 1998 and his former military chief, Ta Mok, died in 2006 in government custody.

Their senior-level colleagues — Ieng Sary, the former foreign minister, and Khieu Samphan, the former head of state — live freely in Cambodia but are in declining health. They are also widely believed to be on the prosecutors' list.

The tribunal was created last year after seven years of contentious negotiations between the United Nations and Cambodia. The government of Prime Minister Hun Sen — a former Khmer Rouge soldier — constantly bullied the world body for control of the joint venture.

With a US$56.3 million (euro42 million) budget limited to three years, trials are expected to begin early next year after countless delays.

The tribunal is a hybrid, with Cambodian judges holding the majority in decision-making matters but needing one supportive vote from a foreign counterpart to reach a super-majority to prevail.

It is operated under the Cambodian judicial system, often described by critics as weak, corrupt and susceptible to political manipulation.