Cambodia began preparations on Thursday to embalm its revered former king Norodom Sihanouk, who will lie in state at the palace for three months ahead of a lavish funeral, a royal aide said.
Chinese experts are helping with the process, which is expected to be similar to the one used to preserve the body of late Chinese leader Mao Zedong in the 1970s, according to Sihanouk's assistant Prince Sisowath Thomico.
"Now the doctors, the scientists are just preparing the body of the king to preserve it," Thomico told AFP.
Hundreds of thousands of mourners packed the streets of Phnom Penh on Wednesday to witness Sihanouk's final journey home from Beijing where he died on Monday of a heart attack aged 89.
Throughout the months that Sihanouk's body will be on view at the palace before it is cremated, groups of relatives will take turns to sit with him, ensuring that the late royal is never alone, according to his aide.
"According to our tradition, members of the royal family will guard the body for 24 hours a day," Thomico said, adding that the same custom was followed in 1960 when Sihanouk's father King Norodom Suramarit passed away.
The prime ministers of Vietnam and Laos are expected to visit the palace on Friday to pay their last respects to Sihanouk, who navigated his country through turbulent decades of war, genocide and then peace.
It is unclear when the doors will open to the general public.
Grieving Cambodians have been flocking to a park outside the royal residence since Monday to pay tribute to the popular former monarch with flowers, candles and incense sticks.
Street vendors were doing brisk business selling freshly printed photos of Sihanouk's homecoming procession and t-shirts emblazoned with his portrait.
Sihanouk, who abdicated in 2004 citing old age and ill health, is fondly remembered for leading the country to independence from France and through a rare period of political stability in the 1950s and 1960s.
But he was also a shrewd political survivor who repeatedly backed different regimes, including the murderous Khmer Rouge whose 1975-1979 reign left up to two million people dead, including five of Sihanouk's 14 children.
After ascending the throne for a second time in 1993 -- he first abdicated in 1955 to play a larger role in politics -- his influence waned as Prime Minister Hun Sen extended his grip on power.
The strongman premier, who has been in office since 1985, vowed to safeguard the royal institution when he paid his respects to Sihanouk's body when it was on view at Beijing Hospital Wednesday before being transported to Phnom Penh.
"I will protect the throne, protect the monarchy, protect the queen-mother and the king," the premier said in images later shown on state television.
Opposition leader Sam Rainsy meanwhile has written to Hun Sen and King Norodom Sihamoni to ask for a special "intervention" allowing him to return to "see the face of the hero-king for the last time", according to copies of the letters that were released by his aides.
The politician lives in France to avoid 11 years of jail time for a string of convictions that critics contend are politically motivated.