BEIJING - In town after town in Sichuan province, shoddily built schools were among the first buildings to tumble during this week's huge earthquake, and officials yesterday found themselves undergoing tough questioning and vowing to punish anyone found responsible.

Public finger-pointing has grown over what one newspaper columnist described as schools that "crumbled like houses of sand" during Monday's 7.9-magnitude quake, which China estimates may leave 50,000 people dead.

A senior official said some punishment might be in the offing. "We cannot exclude the possibility of bad-quality construction of the [school] buildings. We will deal strictly with related problems after investigation," Jiang Weixin, minister of housing and urban-rural development, told a news briefing after touring the quake zone.

The official Xinhua news agency said 6,898 schools were among the 216,000 structures in Sichuan province destroyed by the quake.

In Dujiangyan, near the quake's epicenter, a secondary school collapsed into a pile of rubble while other buildings around it sustained little or no damage.

"To see so many schools in China collapse was a bit surprising," said Reginald DesRoches, a professor of engineering at the Georgia Institute of Technology. "When you see that type of pancaking, you can tell they just weren't designed with any seismic consideration in mind."

Some angry parents who lost their only children blame corruption, saying local officials siphoned off funds earmarked for school construction, throwing up shoddy buildings and pocketing cash.

Experts paint a more complex picture, cautioning against blanket blame. They say radical changes in the last two decades in the way China's government collects and spends money also may be a factor, putting stresses on poorer inland cities and towns with mandates to provide compulsory education through ninth grade but little money to do so. Many schools are built on the cheap, with no regard for building codes.

"Even without the corruption, you'd have substandard schools," said Shawn Shieh, a political scientist who lives in Beijing. "What you have is a problem of resources not going to inland areas. . . . It's part of a larger systemic issue."

During the quake, some huge schools became virtual tombs. Juyuan Middle School in Dujiangyan collapsed and buried 900 students under tons of concrete. In Beichuan, northeast of the epicenter, a high school tumbled around 1,000 or so students; only 360 were rescued. At the Yinghua high school in Shifang County, 300 students were yet to be located. In Mianzhu city, one of the worst-hit areas, seven schools collapsed.

Television and newspapers have carried repeated images of disaster workers removing bodies of children from schools, sometimes laying them out in rows.

In many developed countries, public schools, hospitals and police stations are built using earthquake-resistant standards so they can be used as refugee centers for vulnerable populations. A common way to strengthen buildings is to use steel reinforcement, DesRoches said, but adding steel can increase building costs.

"The main material in these schools is precast slab," said Shi Weixing, head of structural engineering at Tongji University in Shanghai. "Once there's an earthquake, they can be very fragile."