CHENGDU, China — A powerful aftershock destroyed tens of thousands of homes in central China on Sunday, killing six people and straining recovery efforts from the country's worst earthquake in three decades. More than 500 others were injured.
Meanwhile, soldiers rushed with explosives to unblock a river threatening to flood homeless quake survivors.
The fresh devastation came after a magnitude 6.0 aftershock — among the most powerful recorded since the initial May 12 quake, the U.S. Geological Survey said.
The China National Seismic Network said the aftershock was the strongest of dozens since the disaster.
The new tremor killed two people and injured more than 480 others, 41 seriously, the official Xinhua News Agency said. The news agency said today that the aftershock also killed four people and injured 20 others seriously in neighboring Shaanxi province.
Some 71,000 homes that had survived the original quake were leveled, and another 200,000 were in danger of collapse from the aftershock that caused office towers to sway in Beijing, 800 miles away.
Before the aftershock, the Cabinet said the confirmed death toll from the May 12 quake had risen to 62,664, with 23,775 people still missing. Premier Wen Jiabao has warned the number of dead could surpass 80,000.
Landslides jammed rivers across the disaster area, creating 35 new lakes that placed 700,000 survivors in jeopardy of flooding, E Jingping, vice minister of water resources, said in Beijing.
The biggest concern was the new Tangjiashan lake in the Beichuan province, where some 1,600 police and soldiers were hiking with 22 pounds of explosives each to blast through debris, the Xinhua reported.
Hazy weather prevented helicopter flights to the area, and forecasts for rain increased the risk that lakes could overflow.
About 20,000 people have been evacuated from the disaster area, and the total relocated could rise to 100,000, said Liu Ning, chief engineer at the Ministry of Water Resources.
The ministry also said 69 dams in Sichuan were in danger of collapse. Authorities have said the world's largest water project — the Three Gorges dam, about 350 miles east of the epicenter — was not damaged.