BEIJING — Residents of a southern Chinese village near Hong Kong where police opened fire on demonstrators described a tense standoff in the area on Saturday with thousands of armed troops patrolling the perimeter and blocking anyone from leaving.

Frightened villagers said they were either hunkering down at home or arguing with police who are refusing to return the dead to their families.

A Hong Kong newspaper quoted villagers accusing Chinese officials of trying to cover up the killings on Tuesday in Dongzhou, a village in Guangdong province.

Residents said police opened fire on a crowd of thousands protesting against inadequate compensation offered by the government for land to be used for a new wind power plant. Up to 20 were killed, villagers said, while some said dozens more were missing.

It was the deadliest known use of force by Chinese security against civilians since the killings around Tiananmen Square in 1989, which drew an international outcry.

Although security forces often use tear gas and truncheons to disperse demonstrators, it is extremely rare for them to fire into a crowd — as they did in putting down the Tiananmen pro-democracy demonstrations, where hundreds, and perhaps thousands, were killed.

The clash in Dongzhou also marked an escalation in social protests that have convulsed the Chinese countryside over land seizures for factories, power plants, shopping malls and other projects. Farmers often say they are paid too little and some accuse officials of stealing compensation money.

The Dongzhou confrontation is the latest trouble for Chinese officials who have come under international criticism recently for a chemical plant explosion that spilled toxins into a river flowing toward Russia.

Hong Kong's South China Morning Post newspaper on Saturday quoted Dongzhou villagers as saying authorities were trying to cover up the killings by offering families money to give up the bodies of the dead.

"They offered us a sum but said we would have to give up the body," an unidentified relative of one slain villager, 31-year-old Wei Jin, was quoted as saying. "We are not going to agree."