BEIJING, China (CNN) -- China on Monday began three days of national mourning as the death toll from last week's devastating earthquake mounted and rescue workers continued to search for survivors among the rubble.
A woman grieves for her lost mother in Beichuan, in China's southwest Sichuan province. more photos »
The national flag was lowered to half staff at 4:58 a.m. at Beijing's Tiananmen Square as 2,600 people watched the ceremony, state-run media reported.
By Sunday evening, the official death toll rose to 32,477, according to state-run media Sunday. Another 220,109 were wounded in the major quake, the Xinhua news agency said.
Few hopeful relatives were seen in Beichuan, near the quake's epicenter, with soldiers finding many more bodies among the ruins of buildings, The Associated Press reported. Aid teams sprinkled lime on the bodies and disinfected the area.
One bit of bright news came Monday: Two women were rescued after being trapped for nearly one week, Xinhua reported.
The two were found in the rubble of a collapsed building at a coal mine in Sichuan province, Xinhua reported.
Wu Hai, a rescue team leader from neighboring Yunnan province, said bodies were decomposing and "many of the limbs are broken off."
"There are definitely many more here. Locals here said several thousands have been buried here," he told The Associated Press.
But there were a few tales of rescues even six days after the disaster: at least 64 people have been pulled alive from debris.
A 53-year-old man was rescued in Yingxiu town in Wenchuan county near the epicenter 148 hours after the quake, Xinhua said Sunday. The effort took eight hours, the news agency said.
Several others were rescued Saturday by Chinese soldiers, their hands stained with blood from days of digging. More than 4,000 troops were sent to the disaster areas in Wenchuan.
Chinese officials said the three-day period of mourning will begin at 2:28 p.m on Monday, exactly one week after the quake struck the southwestern Sichuan province.
During that mourning period, the Olympic torch relay will be suspended, China's state-run television announced. The torch was going to be in the eastern cities of Ningbo and Jiaxing in Zhejiang Province on Monday, then in Shanghai on Tuesday and Wednesday.
China's state-run news agency Sunday announced that it increased the magnitude of the quake from 7.8 to 8.0. The U.S. Geological Survey measured the temblor at 7.9, which CNN has been reporting. The USGS figure remains unchanged as of Sunday.
The World Health Organization says it fears outbreaks of disease and urged quick action to supply clean water and proper hygiene facilities.
"Ensuring supply of food and safe drinking water and trying to restore good sanitation are critical because these are basic transmission routes for communicable diseases," Hans Troedsson, WHO's representative to China, told AP.
Chinese health officials have not reported any disaster-related outbreaks so far.
So far, almost 60 aid organizations from 13 countries were assisting in the aftermath of the quake. Among the countries are India, France, Singapore, the Philippines and the United States.
Two U.S. military planes landed in Chengdu Sunday with blankets, water and other relief supplies.
The first plane -- a C-17 cargo jet -- flew from a U.S. base in Hawaii, while the second flight came from Alaska, officials said. Watch as U.S. aid arrives in China »
Early Sunday, a strong aftershock rattled areas, while fears of flash flooding and landslides hindered rescue efforts.
Sunday's 5.7-magnitude aftershock shook the region near the border of Sichuan and Gansu provinces just after 1 a.m., the U.S. Geological Survey said.
Just hours earlier, concerns over a damaged dam and rising water levels at two lakes triggered the mass evacuation of 30,000 people -- including rescuers and journalists -- in at least 10 villages and townships, Chinese officials said.
People down-river from the quake-damaged Kuzhu dam in Beichuan county were ordered to leave the area Saturday afternoon over fears it might burst, according to Xinhua.
The two lakes were created when Monday's quake caused landslides that blocked the Qingjiang River in Qingchuan county. Both bodies of water have fast-rising water levels, prompting concerns of flooding, an official at the Guangyuan disaster relief center said.
Monday's quake was the worst tremor to strike China in three decades; a 1976 earthquake killed more than 250,000 people.
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All About U.S. National Earthquake Information Center • China • Sichuan Province • Wen Jiabao
All About China • Earthquakes • Sichuan Province
The government of China announced it would begin three days of mourning on Monday, as the death toll from the 7.9 magnitude earthquake centered in the Sichuan province has been raised to nearly 32,500, with 220,000 injured. At 2:28 p.m local time, flags will be moved to half mast for three days, there will be three minutes of silence, and entertainment in public will be suspended for the mourning period.

A woman being rescued after being trapped for more than 50 hours
Authorities have continued to pull victims out of the rubble resulting from the quake, 65 since the original quake, with two pulled out alive more than six days after the earthquake. Rescuers are also trying to pull out two still alive. More than 9,500 people are still trapped under rubble throughout the province.

Hu Jintao
Chinese authorities are worried as aftershocks continue to affect the region devastated by the initial earthquake, while water builds up in clogged rivers. An 5.8 magnitude aftershock shook buildings and caused people to evacuate in Chengdu, 200 km (125 miles) south of the aftershock's epicenter. The aftershock killed three people and injured 1,000 others. A buildup of water is occurring 3 km (2 miles) upstream of Beichuan, where a man was freed from under a hospital's remains.

Chinese President Hu Jintao said to families of victims in Yinghua that "We will make every effort to save our people even if there is only the slightest hope and possibility." They are preventing people from going into the affected region for fear of these conditions. Families of possible victims who tried to enter the affected region were not allowed into the area by police, due to fears of aftershocks and the clogged rivers.

60 aid organizations from 13 countries have assisted so far with the earthquake, including Japan, Russia, Taiwan, South Korea, the United States and Singapore, and in addition to aid from inside China there has been 6 billion yuan (858 million United States dollars) of aid.