The Unification Church asked followers around the world to pray and fast for its founder, the Rev. Sun Myung Moon, who was unconscious in a Seoul hospital's intensive-care unit Thursday.

Chances of Moon surviving the pneumonia for which he is being treated in the next couple of days are "50-50," the church said on its website, citing an unnamed doctor caring for the 92-year-old.

Moon's church has gained fame around the world since he founded it in Seoul in 1954, notably for its mass weddings. Moon is a self-proclaimed messiah who said that he was 15 when Jesus Christ personally called on him to complete his unfinished work.

The church also runs a multibillion-dollar religious and business empire that includes The Washington Times newspaper and the New Yorker Hotel in Manhattan. Church officials say there are millions of members worldwide, but defectors and critics say the figure is no more than 100,000.

On Thursday, the church called for 40 days of prayer and a three-day fast aimed at inspiring Moon's recovery. Moon's youngest son, Hyung Jin Moon, wrote in a separate message that Moon's family is by his bedside. Moon was hospitalized for complications that arose from an "untimely" cold and pneumonia, the son said.

The Rev. Joshua Cotter, vice president of the Unification Church USA, said Wednesday that the church founder entered the hospital Monday and was in critical condition.

Moon's last major public appearance was last month when he took part in the opening and closing ceremonies of the Peace Cup soccer tournament sponsored by his church in South Korea.