In solemn scenes broadcast on state television, Chinese soldiers performed the daily raising of the national flag at Tiananmen Square in Beijing, but then lowered it to half-mast in memory of victims of the quake in Sichuan province. It was a scene repeated across the country at government buildings as part of the three-day observance, which also was to include a nationwide three minutes of silence at 2:28 pm (0628 GMT), the exact moment the quake struck. The Beijing Olympic torch relay that had been coursing through China also has been halted for three days, Olympic organisers said on Sunday, "to honour the memory of those that lost their lives in the terrible earthquake." All national flags will fly at half-mast at home and at Chinese diplomatic missions abroad from Monday to Wednesday, Xinhua news agency said. "Public recreational activities" also will be halted, it added, giving no details. China on Sunday also suspended the Olympic torch relay nearly a week. The announcements came after a powerful aftershock rattled devastated Sichuan province, killing at least three people and hampering China's efforts to help nearly five million homeless facing the threats of disease and floods. Authorities on Sunday raised the number of confirmed deaths to 32,476 from the quake and revised upward the strength of the quake to 8.0 on the Richter scale. The US Geological Survey has put its strength at a magnitude of 7.9. Sunday's aftershock, with a magnitude of 6.0, shook some of the worst-hit parts of Sichuan, killing at least three people in the town of Jiangyou, local government official Liao Boxun told AFP by phone. People in the town, which was dotted with thousands of blue tents for quake homeless, said the aftershock had spread new fears among a population already traumatised. "When the aftershock hit, mothers hugged their crying children and tried to comfort them, telling them everything would be OK," Dai Yong, who works in Jiangyou, told AFP. The region has suffered at least 24 aftershocks of 5.0 or above on the Richter scale since Monday's quake, amid all-out efforts to rescue more than 9,500 people still buried under the rubble of collapsed structures. Premier Wen Jiabao on Sunday urged scientists at the China Seismological Bureau to improve research on earthquakes and develop better warning systems, the Xinhua state news agency said. Two more people were pulled to safety after improbably surviving six days under the chunks of concrete and other debris, but the pace of such miracle rescues slowed markedly. Officials have estimated the final death toll could eventually top 50,000. China's military said Sunday that all nuclear facilities in the country's earthquake-hit southwest were "safe and secure." "I can say in a responsible manner that all these facilities are safe and secure," senior military officer Ma Jian told a news conference. In a bid to help quake survivors, two US military planes packed with food, power generators and other goods flew into Sichuan province, the first aid that China has accepted from foreign armed forces. A group of 62 elderly tourists emerged from southwest China's quake zone late Sunday for a tearful reunion with family members who had waited anxiously for them for nearly a week. Rescue experts from Japan, Russia, Singapore and South Korea, as well as Taiwan and Hong Kong, have been allowed in to help the effort. Rain also compounded the misery for many of the estimated 4.8 million who have been left without homes. Tens of thousands of people huddled in appalling conditions in the town of Maoxian under leaky makeshift rain covers, in dire need of food, medicine and shelter, the Sichuan News Online site reported. "The people have gone from one disaster to another," the report said. Flood fears also persisted, with the Sichuan government saying landslides triggered by Monday's earthquake had blocked rivers and streams in at least 21 places, causing water levels to swell dangerously behind the rubble. China had already on Saturday evacuated thousands of people in devastated areas near the quake epicentre due to one such blocked river. Worse is possibly to come, with China's national meteorological centre predicting torrential rains later this week in the quake disaster zone, warning they could trigger landslides. The World Health Organisation said Saturday that the lack of safe drinking water or proper waste disposal along with cramped conditions in makeshift camps was "conducive" to disease outbreaks. The military, however, said that nuclear facilities in the region had been checked for signs of any damage and were confirmed safe. Relief workers by Saturday had finally restored land connections with the worst-hit counties of Beichuan and Wenchuan, allowing the full horror of the quake to begin to emerge. Luo Hong, a 22-year-old woman who sells beer, learned that her 55-year-old father, Luo Zaiping, was killed at the coal mine where he worked. "He worked hard his entire life. Originally he wasn't supposed to work Monday and then this happened," she said. Xinhua reported that five employees were killed and at least three pandas were missing at the world-renowned Wolong panda breeding centre, which was heavily damaged. The news appeared to contradict early reports that more than 80 giant pandas at the centre were confirmed safe.AFP