BEIJING — After a year of obfuscation, the authorities on Thursday released the first official tally of student deaths from the earthquake last May, saying that 5,335 children either were dead or remained missing. An additional 546 were left disabled, they said.

Previous estimates placed the number of students who died in the collapse of school buildings during the May 12 earthquake in Sichuan Province as high as 10,000.

During a news conference in Chengdu, Tu Wentao, head of the Sichuan provincial education department, said that the student death figures were accurate.

“These numbers were reached through legal methods,” he said. “We have wide agreement on these numbers.”

The issue of student deaths remains a contentious one here. The parents of children who perished in the rubble of classrooms say the buildings were poorly constructed; the government has largely quashed the issue by harassing or detaining those who insist on pushing the matter.

With the first anniversary of the quake fast approaching, the government has stepped up its campaign to silence those who have been calling for a full accounting of why so many schools failed while adjacent structures remained standing. In recent days, several parents whose children died — and who have refused to stay quiet — said they had been placed under heightened surveillance, and some foreign journalists who have tried to interview grieving parents have been detained.

The newly released numbers did little to quell critics. Ai Weiwei, an artist who is one of China’s best-known gadflies, said the figures were incomplete and “meaningless” because they lacked specifics, like names, ages and places of death. Mr. Ai, who is compiling his own detailed list of the dead, estimates the final figure at around 6,000. He said more precise information from the government might shed some light on the issue of substandard school construction or at least show that the government was truly willing to tackle that fundamental concern.

“The government is trying to escape from the accountability on this matter by postponing or rejecting the publication of details,” he said.

Government officials say that 68,712 people died during the earthquake. Another 17,921 are listed as missing but are presumed to be dead. According to the official media, 7,000 classrooms and dormitory rooms collapsed during the quake.

Over the past year, a number of other people who sought to draw attention to the questions over school construction have been punished or are awaiting trial, including Liu Shakun, a teacher who was charged with “disseminating rumors and disrupting social order” after he posted photographs of destroyed schools on the Internet.

The parents of 126 children who died in Fuxin No. 2 Primary School in the town of Mianzhu have been among the most outspoken — and among those most watched by the government. Sang Jun, who lost his 11-year-old son last year, said in a telephone interview that since Monday, dozens of parents had been watched by about 200 security officers and minor officials sent by the Mianzhu government.

Mr. Sang said an official told him that the parents would be closely monitored until after the anniversary of the quake, and that any contact with foreign journalists was considered “unfavorable to China.”

He and his wife met with a reporter and photographer from The New York Times last week to discuss their grievances. At the time, several parents were willing to secretly meet with journalists in their homes.

Mr. Sang said a half-dozen people, mostly village officials, had been watching his home, but he drove them away after an argument on Wednesday morning. His house, on the edge of a wheat field, is close to the site of the Fuxin school, where new school buildings are being built with money from Taiwan. Mr. Sang said the local government was paying the minders $22 per day to keep an eye on the parents, the school site and roads leading into the village.

Foreign journalists trying to interview parents have been detained, and some had equipment broken by security officers in recent weeks, according to a report issued Wednesday by the Foreign Correspondents’ Club of Beijing, which advocates greater press freedoms in China. A reporter for The Financial Times was punched Tuesday by a thug, possibly a security officer in regular clothes, while conducting interviews around Mianzhu, the group said. After he and his colleagues retreated to their car, they were surrounded by a dozen hostile men, one of whom tried to hit a Chinese news assistant.

Liu Xiaoying, whose daughter died in the Fuxin school, said a French television crew was detained by security officers and led out of the temporary housing camp where Ms. Liu lives after the officers learned that the crew was interviewing her.

On Monday a group of parents from Mianzhu secretly traveled to Beijing and filed a petition at the central government’s petitioning center. It was the third time parents from Mianzhu had tried to file a complaint in the capital.

Employees at the petitioning center immediately notified officials in Mianzhu, who then had people in Beijing detain the parents and escort them back to Sichuan, Mr. Sang said. After the parents returned to Mianzhu on Wednesday morning, they were immediately forced into a hospital and told they would be checked for swine flu, Mr. Sang said.

When asked about the reports of harassment, the head of the publicity department in Mianzhu, a woman who gave her name as Ms. Xu, said, “As far as I know, this doesn’t happen.”