China today outlawed a Buddhist-based spiritual movement that has millions of members throughout the country, accusing its exiled founder of plotting against the ruling Communist Party and inciting his followers to confront the government in a series of protests this week.

In banning the movement, called Falun Gong, the Ministry of Public Security warned that any citizen who posts flyers supporting the group or carries out "any other activities" to encourage the practice of Falun Gong "will be pursued for criminal liability" or sent to a labor camp. Authorities declared that the entire Falun Gong network in China, including 28,000 sites where members practice prescribed exercises, must cease operation immediately. Any attempt to appeal the ban was itself banned.

A number of government actions taken against Falun Gong in recent days underscored Beijing's sensitivity to any potential threat to its stability; its concern about the growing number of millennial sects around the country; and its unwillingness to tolerate the establishment of organizations beyond the party's control. Today's move, which clearly was carefully planned, was accompanied by a barrage of propaganda against the group that aired throughout the day on state media.

Many Falun Gong members said they were shocked by the ban and fear arrest. One professor here who helped publish the books of Li Hongzhi -- the founder and "master" of Falun Gong, who has lived in New York since he left China last year under government pressure -- said he is keeping a low profile. "I haven't gone out," he said nervously by phone.

Li, a former soldier, formulated Falun Gong, or Wheel of the Law, in 1992, combining traditional Buddhist teachings and predictions about the end of the world with meditation and martial arts discipline as a prescription for physical and spiritual well-being. Falun Gong teaches that illness stems from evil and that by following the principles of "truth, compassion and forbearance," one can attain clairvoyance and other preternatural faculties.

Each morning and night, adherents perform Falun Gong's ritual exercises in parks throughout China. Most of them are unemployed, retired, poor or otherwise disaffected -- reflecting the frustration of many members that China's economic reforms had passed them by.

Falun Gong has no stated political goals, but its existence as a quasi-religious group independent of the government -- and one that has proved able to mobilize demonstrators nationwide -- inevitably presented a challenge to China's rulers. However, a crackdown on an organization with anywhere from 2 million to tens of millions of members -- precise figures are not available -- will not be easy.

Three months ago, Chinese security services were taken unawares by Falun Gong, and that apparently set the current crackdown in motion. On April 25, more than 10,000 Falun Gong members surrounded the headquarters of the Communist Party in Beijing in a peaceful sit-in to demand legal status for the movement. Today, officials revealed that Li actually had been in Beijing days before the protest to organize the rally, traveling freely on his Chinese passport. Chinese sources have said the sit-in caused the Beijing government to "lose face."

In an indication of just how deeply the movement has ingrained itself in China, the government acknowledged that Communist Party members had played "key roles" in the movement and thereby "tarnished the image of the party," while the party leadership issued a special order forbidding any of its 60 million members from practicing Falun Gong. President Jiang Zemin also spoke out against the group, outlining a "serious ideological struggle" against it -- another sign of the party's fears about Falun Gong's reach.

Today's announcement followed government detention of more than 70 key Falun Gong organizers, a crackdown that began Monday. Those arrests sparked the most widespread and broad-based anti-government protests in China since the student-led democracy demonstrations of a decade ago. At least 30,000 people rallied in more than 30 cities nationwide Wednesday, calling for the release of the organizers. Smaller protests occurred again today despite a massive police presence in Beijing and other major cities.

In its propaganda offensive today, the Beijing government concentrated its attack on Li. The New China News Agency and China Central Television called him an "evil person" and accused him of defrauding his followers. In a telecast aired four times in close succession, Falun Gong was made out to be a practice that could cause insanity, violence, alienation and suicide, and former Li associates were trotted out to denounce him.

The government attack also emphasized Falun Gong's intricate and far-flung organization, reflected in its ability to quickly mobilize large, determined crowds -- no small feat in an authoritarian country. The government said that the group used its 39 general offices, 1,900 teaching stations and thousands of "practice areas" to organize demonstrations nationwide. Beginning in June 1998, members of Falun Gong protested outside at least 20 media and other government organizations that had criticized its practices, the government said.

Falun Gong adherents in the United States condemned the government action. Shawn Lin, a spokesman in Washington, estimated that Chinese police had arrested or detained as many as 30,000 Falun Gong members; a government official said fewer than 1,000 had been arrested.

CAPTION: Just hours before the Chinese government declared Falun Gong illegal, members took part in a meditation and exercise session in the southern city of Guangzhou.