As police battled to suppress deadly ethnic clashes last week in central China, tens of thousands of rice farmers fighting a dam project staged a huge protest in the western part of the country. The same day, authorities crushed a strike involving 7,000 textile workers.

A week earlier, a large crowd of retirees demanding pension payments blocked traffic for days in a city in the east; nearly a thousand workers demonstrated outside a newly privatized department store in the northeast; and police used rubber bullets and tear gas to quell a giant mob of anti-government rioters in a western city.

The string of disturbances, described by local journalists, witnesses and participants, highlights the daily challenge that civil unrest now poses to the ruling Communist Party. Despite historic economic growth that has lifted millions out of poverty, protests and riots in the world's most populous country are occurring with increasing frequency, growing in size and ending more often in violence.

This expansion of social strife has yet to shake the party's authoritarian grip on power. But the trend, evident in the government's own police statistics, has prompted alarm at the highest levels of the Chinese leadership, which has repeatedly declared social stability its top priority.

The Communist Party has indicated it is worried that these outbursts of discontent might coalesce into large-scale, organized opposition to its rule. The concern was apparent in a report by its Central Committee in September urging officials to improve governance and warning that "the life and death of the party" was at stake.

"The Soviet Union used to be the world's number one socialist country, but overnight the country broke up and political power collapsed," Vice President Zeng Qinghong wrote last month in the People's Daily, the party's flagship newspaper. "One important reason was that in their long time in power, their system of governing became rigid, their ability to govern declined, people were dissatisfied with what the officials accomplished, and the officials became seriously isolated from the masses."

There were more than 58,000 major incidents of social unrest in the country last year, about 160 per day on average, according to the party magazine Outlook. That was an increase of 15 percent over 2002 and nearly seven times the figure reported by the government just a decade ago. Another study of police statistics, by Murray Scot Tanner, a scholar at the U.S.-based Rand Corp., concluded the demonstrations were growing in size while violence, including attacks on party and state officials, was also on the rise.

"Research institutes like our center are working on this issue day and night, and so is the government," said He Zengke, executive director of the China Center for Comparative Politics and Economics in Beijing. "We all know the importance and urgency of the problem."

The incidents that erupted over the past two weeks illustrate the wide variety of factors behind this wave of unrest: tensions between the Han ethnic majority and ethnic and religious minorities such as the Muslim Hui; a widening wealth gap and persistent government corruption; the seizure of farmland for development; and layoffs associated with the transition from socialism to capitalism.

The party once blamed domestic unrest on subversives and foreign agents, but it now acknowledges that many taking part in these protests have legitimate grievances. Officials also recognize that protests are inevitable in a rapidly changing country and can serve as a safety valve for pent-up public anger.

Wang Yukai, a professor at the National School of Administration, which trains government officials, said most protesters were among the poor who have suffered in the transition to a market economy and have been unable to protect their rights through approved channels. He said the party's recent call to improve governance is an attempt to address this problem by making officials more responsive to the public and less corrupt.

But the party, under the leadership of President Hu Jintao, has ruled out democratic reform as an option, choosing instead to experiment with broadening its base and making leaders more accountable to party members. It has also adopted a carrot-and-stick approach toward protests, giving in to some demands while arresting activists and taking firm steps to prevent demonstrations from spreading.

One of the party's key weapons is the control of information; officials restrict or bar news reporting of all social unrest. But with the growing use the Internet and e-mail, widening access to overseas news media and the prevalence of cell phones and text messaging, censorship is becoming more difficult.

Word of a traffic dispute between Han and Hui villagers in central Henan province spread so quickly last week that thousands rioted before police could respond. More worrisome for the authorities, residents reported that hundreds if not thousands of Hui from other parts of China learned of the clashes by telephone and rushed to the region.

Similarly, an altercation a week earlier in the western city of Chongqing between a deliveryman and a fruit market worker attracted a crowd of thousands within hours because the worker passed himself off as a government official and threatened to use his influence to resolve the dispute. The incident sparked a riot in which residents set fire to police cars and looted government offices. Local authorities attempted to impose a news blackout, but photos and accounts of the riot quickly appeared on the Internet.

The efforts of party censors sometimes help fuel unrest by allowing rumors to fly without challenge. In Henan, residents reported hearing inflammatory and contradictory accounts of what sparked the violence. Meanwhile, in western Sichuan province, farmers who massed at the site of a proposed dam and staged one of China's largest rural protests in recent years gave differing versions about demonstrators being beaten to death by police.

Many farmers said they were among a crowd of more than 60,000 that carried the body of a colleague to a government building in Hanyuan County in protest. But Gao Qiansheng, 38, one of the farmer activists, said the body was that of a young farmer who died in a motorcycle accident on the way to the protest. He said no one was beaten to death, though at least two people were injured in a scuffle with police.

The government's response to that protest and the other recent incidents illustrates its growing sophistication at managing civil unrest.

Gao said tens of thousands of farmers whose land would be flooded by the dam were protesting the meager relocation and compensation package offered by the government. The demonstration began Wednesday at the dam site and continued until Friday, when senior local officials persuaded the farmers to return home by pledging not to begin construction until their concerns were addressed.

Meanwhile, authorities in Xianyang, a mid-sized city in Shaanxi province, succeeded in ending a labor strike that had lasted seven weeks, the longest known to have occurred in China in recent years. Police had refrained from violence at the former state textile mill, worried about sparking a riot, and chose instead to slowly identify worker activists and arrest them one by one, witnesses said. The authorities then offered partial concessions to the 7,000 workers, persuading most of them to return to the factory on Sunday.

Residents said authorities also promised concessions to defuse two large labor protests in other cities a week earlier. But the party's approach -- some officials call it "buying stability" -- sends the message that protests are the most effective way to seek redress from the government, and the more people involved the better. After the farmers protesting the dam in Sichuan disbanded, they worried that local officials were breaking their promises. On Wednesday, witnesses said, more than 10,000 protesters returned to the site.

Researchers Jin Ling, Zhang Jing and Vivian Zhang contributed to this report.

Chinese paramilitary police patrol on a bridge in Henan province after violence between members of the Han ethnic majority and Hui Muslims.A Hui Muslim stands in a village mosque in central Henan province. Residents said Hui from elsewhere in China rushed to the region after hearing of ethnic clashes there last week.