Later, a 53-year-old man was pulled from the rubble in the devastated town of Yingxiu, after surviving for 148 hours.
At least 63 people were rescued alive a day earlier.
State television reported that rescue crews in the quake-ravaged region had gone on heightened alert following the overnight aftershock, fearful further strong tremors could hurt their teams.
"Rainfall and the aftershock have added difficulties to rescue efforts," it said, giving no details.
China has experienced more than 20 aftershocks of 5.0 or above on the Richter scale since the initial earthquake last Monday.
Al Jazeera's Tony Cheng, reporting from Dujiangyan, said hopes of finding more survivors were fading.
"The rescue operation seems to be moving from recovery of the living to removal of the dead," he said.
"It's unlikely we're going to see many more survivors now than we've been seeing in the last few days."
The government says it expects the final toll to surpass 50,000 people.
More than 4.8 million people have been left homeless.
China on Sunday revised upwards the magnitude of the earthquake to 8.0 on the Richter scale.
China's revision of the earthquake's magnitude to 8.0 is likely to be noted by the superstitious.
Eight is a lucky number in China.
The Beijing Olympics are set to open on August 8, 2008 at 8:08pm.
Many on the internet have also commented that the earthquake itself took place exactly 88 days before the opening ceremony.
Beijing also declared three days of national mourning, to start on Monday, for victims of the earthquake.
The Olympic torch relay will also be suspended during that time.
Beijing Olympic organisers said in a statement on Sunday that the suspension would "express our deep mourning to the victims of the earthquake".
The government is also ordering all flags be flown at half-staff and a halt to all public recreation activities.
The official People's Daily newspaper urged a nationwide "battle" against the disaster amid a rush by Chinese to volunteer.
"More than ever, people are aware that to win the battle against the devastating earthquake requires the contribution of the whole country," the newspaper said in a commentary.
As rescue work resumed on Sunday, flood threats from blocked rivers appeared to have eased, after three backed-up rivers overflowed without causing major problems, state media reported.
Xinhua quoted Liu Ning, engineer-in-chief with the ministry of water resources, as saying some facilities, such as reservoirs and hydroelectric stations, have been damaged but that no reservoirs burst.
Worries about possible flooding had earlier sent thousands of people fleeing the area.
More than 10,600 people are known to be still buried nearly a week after the earthquake shattered tens of thousands of buildings in dozens of towns and cities in Sichuan, Xinhua said, citing regional officials.
Experts say buried earthquake survivors can last a week or more, depending on factors including the temperature and whether they have water to drink.
Hu Jintao, the Chinese president, has urged rescue teams to reach remote villages battered by the earthquake, according to Xinhua.
The number of security forces helping victims rose to almost 150,000, and the government added cash payments of $715 to each family that lost a member.
But some residents in the earthquake-hit areas complained the government was not doing enough.
|Rescue efforts continued on Sunday, despite|
threats of further aftershocks [AFP]
The Associated Press said that one of its reporters was stopped at a petrol station in Miangyang city on Sunday, by a group of about 15 people appealing for help for their village, Xiushui.
"The government is doing nothing to help us," said one man, handing over a note which said it had been signed "by the people of Xiushui".
More than 200 rescuers from Japan, Russia, South Korea and Singapore have been searching alongside Chinese soldiers.
International aid continued to arrive, with a US air force cargo plane landing in the Sichuan provincial capital of Chengdu on Sunday, carrying tents, lanterns and 15,000 meals.
Chinese authorities are also battling to prevent the outbreak of disease, with the risks heightened by the rotting carcasses of 12.5 million livestock and poultry.
"Combating epidemics is the most urgent and the biggest task facing us right now," Wei Chaoan, vice minister of agriculture, said on Saturday.
The World Health Organisation said that the lack of safe drinking water or proper waste disposal along with cramped conditions in temporary shelters was "conducive" to outbreaks.
"Preventing communicable disease outbreaks is the key public health issue now facing the People's Republic of China," the UN body said in a statement.