Chinese Group Has U.S. Voice

American followers of Falun Gong rushed to Capitol Hill Monday, CBS News' Sharyl Attkisson reports.

They're lobbying Congress to intervene in China's massive crackdown on the spiritual group Chinese officials have labeled "an evil cult."

Last week, China outlawed Falun Gong, arresting leaders and herding practitioners by the thousands into stadiums. A senior U.S. official tells CBS News that China's aggressive stance against a peaceful group with no apparent political motive shows how far China will go when confronted with a large movement outside of the Republican party.

Publicly, U.S. officials are less vehement, but today National Security Advisor Sandy Berger said China has been put on notice.

"We obviously believe that people in China and elsewhere should have the right of assembly and the freedom of expression," said Berger.

But the truth is, U.S. officials just don't know much about Falun Gong, even as 100 million Chinese and a growing number of Americans are said to be followers. It's a mysterious mix of martial arts, moral teachings and meditation to achieve a healthy body and soul.

Its popularity has exploded largely in the absence of founder Li Hongzhi, who left China under pressure last year, and now lives in New York.

In his first network interview, Li told CBS News: "People with a healthy body and high morality are good to society and good for the government. I feel puzzled why the government is so upset about it."

The reason may be its massive appeal. Many Chinese are turning to Falun Gong instead of the Communist party for guidance. The conflict may be the most serious internal threat since the Tiananmen Square uprising ten years ago.