Tens of thousands of students at more than 30 universities and colleges in Beijing boycotted classes Monday to press demands for democratic reforms, student leaders said.

"All 21 universities in our coordinating committee were joined by more than 10 other schools," said a student leader at Beijing University.A rally of more than 4,000 students at the university stadium broke up in chaos after some activists accused a fellow organizer of being an infiltrator working for the authorities.

Residents of two provincial capitals - Xian and Changsha - said tension was running high there after rioting over the weekend linked to the death of former communist party leader Hu Yaobang.

Teachers in Changsha in Hunan Province quoted students as saying 300 to 400 people had been arrested and that rioting continued for a second day Sunday. Only a few students were involved.

A Changsha official said only 20 to 30 people had been arrested.

In the central city, Xian, foreign students said the authorities had stopped them leaving their campuses after rioting Saturday in which 130 policemen were injured, according to official accounts.

Residents spoke of unconfirmed reports that one policeman had died. A city spokeswoman said she did not know about it.

Hu's death of a heart attack April 15 ignited campus unrest and student rallies for reforms grew into the biggest demonstrations seen in the capital since 1976.

Around 100,000 people took part early on Saturday shortly before Hu's funeral, attended by China's top leaders.

Student leaders in Beijing said they were preparing leaflets to explain their cause to outsiders.

A poster at a university urged a letter campaign to friends and relatives throughout China to spread the news about the students' demands and protests.

"Striking is our final resort. We must strike with our whole heart. If we don't get freedom and democracy we won't stop the strike," proclaimed a poster at People's University.

Campus leaders planned to strike indefinitely.

Foreign teachers contacted at universities in other major cities said students were attending classes.

China's official media responded Monday to the student protests and rioting by promising more democracy but only at a pace dictated by the Communist Party.

The party newspaper People's Daily warned that "chaos under heaven" would be disastrous for China's modernization.

"How slowly is slowly?" asked a student leader. "We have to make sure slowly doesn't mean it doesn't come."