WASHINGTON (AP) _ Religious persecution against both Christians and Buddhists has increased in China since the Clinton administration extended most-favored-nation trading status last year, witnesses told Congress Wednesday.

Amid reports this week of dissident arrests and the police killing of a Chinese Protestant arrested at an underground church service, human rights and academic witnesses chronicled widespread abuses at a congressional hearing.

''I hope when Secretary Christopher meets with the Chinese leadership later this week, he will emphasize our revulsion and outrage at China's vicious campaign of religious persecution,'' said Rep. Tom Lantos, D-Calif., chairman of the House Foreign Affairs subcommittee on human rights, who held the hearing as Secretary of State Warren Christopher prepared for a weekend visit to Beijing.

''China hasn't even come close to making the progress that would allow the administration, in good conscience, to seek'' an extension of trade privileges, said Rep. Chris Smith, R-N.J., who led a U.S. delegation to China in January.

Just six weeks before Christopher's visit, Premier Li Peng signed two decrees prohibiting foreign missionary work, prohibiting unauthorized religious ceremonies and banning financial activities with overseas religious groups, said Joseph M.C. Kung, president of the Cardinal Kung Foundation, a U.S. group working for religious freedom for Chinese Roman Catholics.

''These laws legitimatize the authorities to arrest anyone whom they dislike in the name of illegal religious activities,'' Kung said.

He said China is ''daring the United States'' to lift most-favored-nation trade status when it comes up for review in June.

Jeffrey Hopkins, director of the Center for South Asian Studies at the University of Virginia, said, ''The Chinese government's suppression of monks and nuns in Tibet has always been violent but is now immediate and for minor reasons.'' Hopkins said he has been in Tibet five times since 1986 and has seen increasing signs of Chinese domination.

Anne Himmelfarb of the Puebla Institute, another Christian human rights group, gave the subcommittee a list of 65 Catholic bishops, priests and lay persons as well as 44 Protestants arrested in recent years.

Lodi G. Gyari, president of the International Campaign for Tibet, said the Chinese have taken no steps since most-favored nation status was extended to protect Tibet's religious and cultural heritage ''and continues to persecute the Tibetan people for their religious and political beliefs and practices.''

A U.S. religious group, News Network International, reported Wednesday that a Chinese Protestant who attended a church service in defiance of Communist Party rules died after police arrested him in January, hung him by his ankles and beat him. The man, Zheng Musheng, was one of millions of Chinese who worship in churches set up in private homes, the group said.