Thousands of tearful, flower-carrying mourners descended Thursday on the South Korean headquarters of the Unification Church to offer prayers to their late "messiah" Sun Myung Moon.

Men clad in black suits and women in white dresses flooded the church's main compound in Gapyeong, 60 kilometers east of Seoul, at the start of a 10-day wake ahead of Moon's funeral on September 15.

Moon, the self-styled messiah who founded the church famed for its mass weddings and business empire spanning cars to sushi, died Monday at the age of 92 due to complications from pneumonia.

From early morning, buses ferried mourners - including a large number of Japanese - into the sprawling, mountain-ringed Gapyeong complex, where a special altar bearing a giant portrait of a youthful-looking Moon had been erected inside a cavernous, covered stadium.

They offered roses and lilies - Moon's favorite flowers - and bowed before the portrait ringed with roses.

The altar was flanked by the flags of South Korea, Japan, the US and other countries, as well as floral tributes from prominent figures including South Korean President Lee Myung-bak.

The atmosphere was somber but calm, as Moon Hyung-jin, Moon's youngest son and successor as church leader, received the mourners, who included women with infants in strollers.

Many wept quietly as solemn music played in the background.

Bo Hi-pak, Moon's close aide, urged church members to rally behind Moon's two sons and his wife to continue their founder's legacy.

"The father told us not to cry and not to show sorrow when he's gone, so everyone's trying hard to follow his words," he told AFP before bursting into tears. "But we're too devastated."

Hundreds of students from church-owned schools and dancers from a church-run ballet troupe were among those who paid tribute at the altar, under a giant banner reading "Sun Myung Moon: The true parent of heaven, earth and humankind."

Selected senior church members and VIP mourners were allowed to view Moon's body, which had been laid out in a glass-topped coffin in one room of a vast White House-modeled hillside mansion.

Moon's reclining body was clothed in a heavily brocaded red and gold robe and a silver crown placed on his head.

Following a personal condolence message from North Korean leader Kim Jong-un, there had been speculation that Pyongyang might send a rare delegation to the South to attend the September 15 funeral. But a senior church official said Thursday that Pyongyang had decided to stay away, amid lingering resentment over a recent South Korean-US military drill.