Ny JORDBÄVNING - 7.8 - 12 maj morgon

BEIJING, China (CNN) -- Thousands of people have been killed by Monday's powerful earthquake in just one affected region of central China, its government said, with the toll expected to keep rising as bodies are retrieved from schools, homes and factories.

The death toll quickly rose throughout the day. State-run news agency Xinhua said it had reached 8,533 in Sichuan Province by Monday night, and another 10,000 were believed to be injured.

It reported that authorities were yet to reach Wenchuan County -- which sits at the epicenter of the 7.8-magnitude earthquake with a population of about 112,000 -- because of damage to roads.

In Beichuan County, close to Wenchuan, the number of deaths was estimated at more than 3,000, with 80 percent of the buildings destroyed.

In addition, at least 48 people were killed in the northwest Gansu Province, Xinhua said.

Several hundred students were also feared to be buried in collapsed school buildings, the agency said.

China's Seismological Bureau said the earthquake had affected more than half the country's provinces and municipalities.

President George W. Bush released a statement saying the United States "stands ready to help in any way possible."

"I am particularly saddened by the number of students and children affected by this tragedy," Bush said.