China has announced three days of national mourning as the death toll from last Monday's earthquake continues to rise.
Chinese government buildings will fly the national flag at half-mast for three days starting tomorrow and the Olympic torch relay will also be suspended.
The death toll from the disaster has risen to 32,476, according to state news agency Xinhua.
At least three people were killed this morning as a powerful aftershock rattled the country's southwest region.
The 6.0-magnitude tremor shook some of the worst-affected parts in Sichuan province.
The latest aftershock has affected efforts to find survivors and help nearly 5m people facing the risk of disease and flood.
China has suffered more than 20 aftershocks of 5.0 or above on the Richter scale since last Monday's initial 7.9-magnitude quake, amid all-out efforts to rescue more than 10,000 people buried under the rubble.
One survivor was pulled out today after 139 hours under the debris of a flattened hospital in the ravaged Sichuan provincial town of Beichuan.
At least 63 more people were rescued alive yesterday, the Xinhua news agency said, defying experts' warnings that survival chances greatly diminish three days after an earthquake.
State television reported rescue crews in the region had gone on heightened alert following the overnight aftershock, fearful further strong tremors could hurt the teams.
It said rescuers were still trying to determine if there were any casualties from the aftershock.
Relief workers had cleared through landslides and completed repairs to restore land connections with the worst-hit counties of Beichuan and Wenchuan before the latest aftershock.
The full horror is now emerging nearly a week after the earthquake which damaged more than 15m buildings in the remote, mountainous area that has escaped much of China's soaring economic growth.
Major challenges lay ahead, with more than 4.8m people left homeless.
Thousands of people were evacuated in Sichuan province yesterday over fears of floods due to a landslide that had blocked a river.
Rainfall also sent a mud-rock flow into a quake-hit town in Gansu province, which neighbours Sichuan, threatening to demolish more homes.
Authorities are also racing to prevent the outbreak of disease, the risks heightened by the rotting carcasses of 12.5m livestock and poultry.
The World Health Organisation says that the lack of safe drinking water or proper waste disposal along with cramped conditions in temporary shelters is conducive to outbreaks.
China's president Hu Jintao, on a tour of Sichuan province, offered thanks to the foreign governments and organisations that provided help after the quake.
Teams from Japan, Russia, Singapore and South Korea, as well as Taiwan and Hong Kong, have been allowed in to help the effort, although other offers from elsewhere have been declined.