BEIJING — Government officials have acknowledged in the most definitive report since the devastating earthquake in Sichuan Province in May that many school buildings across the country are poorly constructed and that 20 percent of primary schools in one southwestern province may be unsafe, according to a description of the report published by the state media on Friday.

The Ministry of Education report is a rare government admission of substandard school construction. The issue has been a delicate one since the earthquake, which killed 88,000 people, many of them children crushed in shoddily built schools.

The report called on the central government to finance the reconstruction of vulnerable schools quickly, especially those in rural areas and western parts of China that are seismically unstable. Speaking about the report, Lu Yongxiang, vice chairman of the National People’s Congress Standing Committee, said in an interview with the China News Service that Beijing would increase construction subsidies by 25 percent to 150 percent, depending on the region.

Mr. Lu was quoted as saying that nearly 2.5 percent of all primary and middle schools in China have structural problems, on a built area equal to 360 million square feet.

He added that 90 percent of these schools were in rural areas and the earthquake-prone west of the country. The China News Service report singled out Yunnan Province, just south of Sichuan, as having some of the most structurally unsound schools. It said 20 percent of the province’s primary schools and 11 percent of its middle schools were structurally unsound.

Mr. Lu’s point was underscored just hours after the report was made public. On Friday morning, a 4.9-magnitude earthquake shook Yunnan Province, injuring nine people, according to Xinhua, the official news agency.

In Sichuan, many parents of students killed in May continue to press their demands for an investigation into the school collapses. This month, a group of parents whose children died at a primary school in Fuxin filed a lawsuit against government officials and a construction contractor. The suit asked for $1.1 million in damages and a public apology.

But last week a judge at the Intermediate People’s Court in the city of Deyang rejected the lawsuit, saying the court was hamstrung by a government directive from on high. The parents said they would pursue the case to the nation’s highest court.

The number of students who died in the May earthquake is unknown, although estimates suggest the figure may be as high as 10,000. In his comments to the state media, Mr. Lu, the standing committee vice chairman, opened a small window into that mystery: He said that 14,000 schools in Sichuan had been damaged by the earthquake.