The 28 were ''suspected of instigating'' the riots that flared in the Guangxi region last week, the Xinhua news agency reported. It did not specify their identities or the charges they faced.
Villagers attacked officials and burned cars in protest against attempts to enforce family-planning policies they called harsh and unjust, witnesses earlier told Reuters. Xinhua also said protesters damaged government offices and files.
The Xinhua report was the first public official statement about the protests, and it blamed traditional-minded locals in Bobai county, where it said seven towns saw riots late last week. The main riot involved about 300 residents in the town of Dungu on Thursday, it said.
But the report also made clear that sweeping family-planning penalties lay behind the discontent.
''Violations of the family planning policies are common in Bobai as local residents still hold to the traditional idea that having more children brings more happiness,'' Xinhua said.
''The county's family-planning workers have carried out large-scale law enforcement campaigns,'' it added.
A local official told Xinhua that the rising population was squeezing land availability. But a county government chief suggested that not all the blame lay with residents.
''There may be problems with the family planning work of the government, which have prompted complaints from residents,'' Huang Shaoming, the head of Bobai, said.
Some couples with more than one child must pay fines of up to tens of thousand yuan (thousands of dollars), villagers earlier told Reuters.
China launched its one-child policy in 1980 to curb a ballooning population, now at more than 1.3 billion.
The restrictions, which vary from city to countryside, have bolstered a traditional preference for boys and have drawn fire from Western countries and human rights watchdogs after reports of forced abortions and infanticide.
Faced with swelling rural discontent, China's Communist Party leadership has sought to defuse protests by promising to rein in official abuses and inequality while also bolstering police controls on ''mass incidents.'' Yulin city, which oversees the riot-hit area, sent 4,200 officials to 28 towns in an effort to defuse the complaints of locals, Xinhua reported.
Reuters AB GC2243