BEIJING, DEC. 19 -- Washington's top official for human rights said today that he has asked for the release of 150 Chinese political prisoners, and he appeared hopeful that his two days of intensive talks with senior judicial and police officials may signal a new flexibility in China's position.

Assistant Secretary of State Richard Schifter said he was unable to predict the outcome of the talks but he was hopeful that persistence in focusing on human rights abuses in China eventually would pay off. He spent years raising similar issues with Soviet authorities.

Schifter said that in 16 hours of meetings, Chinese officials did not once make their standard denunciation that outside criticism of Beijing's human rights record constitutes interference in China's internal affairs.

"We had fruitful conversations," he said. "It was a matter of discussing the issues. It was not a matter of their saying, 'Butt out.' "

Schifter's visit was the first to China by an assistant secretary for human rights. He said he also discussed China's policy toward religious practitioners, including those in Tibet, its one-couple, one-child family planning policy, and harassment of Chinese students studying abroad.

The visit had been under discussion for several months, but was accepted by the Chinese only after Foreign Minister Qian Qichen met with President Bush Nov. 30 in Washington. Schifter leaves for another day of talks in Shanghai on Thursday before returning to Washington.

Ambassador James R. Lilley, who was involved in the lengthy negotiations to allow Chinese dissident Fang Lizhi to leave the country earlier this year, said he was surprised by the breadth and depth of this week's talks.

"Judging from the way the two sides were snarling at each other across the table one year ago, at least the atmospherics have substantially improved," he said. "Attitudinally, you've got a sea change. Whether it ends up in concrete results remains to be seen."

The visit comes at a sensitive time for China. Beijing is preparing to try dozens of intellectuals and student leaders for counterrevolutionary crimes in connection with last year's massive protests for democratic change, according to Chinese sources and government announcements. Trials of at least three students -- two of whom were on a list of the government's 21 most-wanted student leaders -- began in late November, according to official court notices. No verdicts have been announced.

Schifter said he did not talk about specific cases with the Chinese but was told that those cases connected with last year's protests had not yet reached the prosecution stage.

U.S. officials declined to release their list of 150 prisoners but said it included students, intellectuals and workers connected with last year's democracy movement, activists from the 1978 Democracy Wall movement, Tibetan clerics, and Catholic priests.

One person who was singled out, Schifter said, was Wei Jingsheng, who as a principal in the placing of posters on Beijing's Democracy Wall was one of Communist China's earliest and most prominent dissidents.

Wei, reported to be suffering from schizophrenia, is serving a 15-year sentence for advocating democratic safeguards to prevent a Communist dictatorship.

Schifter presented the list of 150 names in a meeting with officials from the Ministry of Public Security, and said he expressed hope for a further review on a case-by-case basis. He said he told officials that "a government in control of the army and security forces could not really be threatened by unarmed students."

He said he did not make any explicit warnings of American reaction to harsh treatment of Chinese political prisoners but told them of the sentiment in Congress reflected in the overwhelming House passage this fall of a measure to impose tough human-rights conditions on any extension of China's most-favored-nation trading status.

China's trade now measures more than $70 billion annually. The favored U.S. trade status is vital to China's ability to export, and it must be renewed every year. Some congressmen have said this issue is likely to be raised when Congress reconvenes early next year.

At the same time, Chinese sources said it was unlikely that the leadership will allow another mass release of political prisoners because that would undercut its legitimacy. "They called last year a 'counterrevolutionary rebellion,' " said one Chinese. If too many are freed, "how can they call it a rebellion without any rebels?"

According to one Chinese source, 36 persons, almost all of them students and intellectuals, have been formally arrested in recent weeks and charged with counterrevolutionary crimes associated with their alleged key roles in last year's demonstrations. They include scholars Wang Juntao and Chen Ziming, who have been charged with sedition, a crime punishable by death, and with counterrevolutionary propaganda and agitation. Student leader Wang Dan has been accused of spreading counterrevolutionary propaganda.

Most of these activists have been jailed for more than a year at Qincheng prison, a maximum-security jail for political prisoners.

It is not clear when the rest of the trials will take place. Under Chinese law, prosecuting authorities have two to three months after the notification of formal arrest to prepare the indictment. The trial usually begins within a week to 10 days after the indictment has been presented.

But according to one Chinese source, the trials could be delayed until March or April, after the annual meeting of the National People's Congress, China's rubber-stamp legislature.