The arrest of a U.S.-based academic on charges of illegally collecting intelligence has prompted one of the strongest human rights campaigns ever from American scholars specializing in Chinese studies, including a petition calling for his release.

More than 68 top American and international scholars of China have signed a petition urging freedom for Song Yongyi, a librarian at Dickinson College in Carlisle, Pa., who has been held in China since August on charges of obtaining secrets. A separate petition on the college's Web site has more than 1,900 signatures.

"Everyone from China scholars to elementary school children . . . is signing their names," said David G. Strand, a Chinese history professor at Dickinson.

The campaign is unusual because American experts in Chinese studies have been reticent about criticizing China's human rights record. Many American academics have remained silent about the arrests of Chinese dissidents, religious figures or intellectuals either out of fear that Beijing will block them from completing research projects or because they disagree with what some call an over-emphasis in the Western media on China's human rights record.

But Song's arrest has galvanized China scholars in the United States, prompting some to call on Washington to limit academic exchanges with China and others to urge Song's release. It also has sent a wave of fear through the ranks of American graduate students and scholars working in China.

"I'm studying a totally obscure subject in the Qing Dynasty, but when I heard about Song I stopped for a second and thought, 'Could they come and get me?' " said one American graduate student, who asked that her name not be used.

Song, who was born in China, came here last summer to collect materials on the Cultural Revolution, which occurred between 1966 and 1976. He was detained Aug. 7 for obtaining what were alleged to be secret documents. On Christmas Eve, the Chinese government told Song's wife that he had been formally arrested, making imprisonment a near certainty.

The petition by leading American scholars issued this warning: "Continued prosecution of this case will make it impossible for foreign scholars or Chinese scholars associated with foreign universities to conduct research in open sources in China with the confidence that they will be safe from criminal prosecution."

Michel Oksenberg, a Stanford University professor, said the case "would appear to violate a basic principle of reciprocity that has governed academic exchanges between our two countries." A former top official at the National Security Council and a respected academic not given to hyperbole, Oksenberg urged China to explain its case.

Oksenberg said that "the charge against Song is so vague--that he conveyed intelligence to a foreign organization--that it raises questions about the safety of any foreigner in China."

Chinese officials have declined to discuss the case.

Song is a permanent resident of the United States and was to be sworn in as a citizen in September. He is a nationally recognized authority on the Cultural Revolution.