(CNN) -- More than 600 members of a fringe Christian group in China have been detained for spreading rumors of an impending apocalypse, pegged to the Mayan calendar, China's Xinhua news agency reported.
Known as the Almighty God cult, the group latched on to the Mayan doomsday scenario to predict the sun would not shine and electricity would not work for three days beginning on December 21.
The cult was established in 1990 in central China and requires its members to surrender their property to the group.
Group members have spread doomsday rumors door-to-door or at public venues and claimed only they could save people's lives, according to authorities.
December 21, 2012, is the endpoint of a more than 5,000-year Great Cycle marked on the "Long Count" calendar of the Mayans, an ancient Native American civilization from Mexico and Central America.
Some say this date marks the end of the world, while others suggest it marks the beginning of a new era.
Most of the cult members seized by police were detained for five to 10 days for disturbing social order, Xinhua reported. Police have seized a large number of leaflets, banners, computer discs, slogans, books and printing machines.
Arrests have been reported in Qinghai, Sichuan, Guangdong, and Guizhou provinces and in the capital, Beijing.
"Advice before catastrophe: Satan's men will be extinct. Only the 'Almighty God' can save man. Anybody who resists God will go to hell," a leaflet said.
Cao Wei, a police officer with the Shanghua police station in Lanxi City, said cult members ask new believers to write letters of assurance to show their loyalty to the "Almighty God" and to evangelize.
Xinhua reported that one member wrote a letter saying, "I must preach to 100 people today, or I will be cursed."
Most of the cult's members are in their 40s, unemployed people in urban areas or low-income groups affected by illness or disaster. The group believes that Jesus has been resurrected as a Chinese woman, Xinhua reported.
Authorities say the cult intimidates people who try to leave.