One person was confirmed dead and 25 others were seriously injured when a strong aftershock measuring 6.4 on the Richter scale jolted Qingchuan County of southwest China's Sichuan Province on Sunday afternoon.

"The death and 24 injuries were all reported in collapsed houses or landslides," said Wang Fei, an official with the disaster relief office in Guangyuan City. He said details of the victims were not immediately available.

Another injury was reported in Wenxian County of the northwestern Gansu Province, which borders Qingchuan.

"No death has been reported so far, but many ramshackle houses in the town seat collapsed in the aftershock," said Zhu Lin, an official in Bikou town of Wenxian County.

The strongest aftershock since the 8.0-magnitude quake of May 12 hit at 4:21 PM was felt in many parts of the province, including Sichuan's capital Chengdu, said Hou Jianmin, a senior engineer with China National Seismic Network.

The network has located the epicenter of the tremor at 32.6 degrees north latitude and 105.4 degrees east longitude in Qingchuan county of Guangyuan City, which sits on the northeastern border of Sichuan Province and neighbors Gansu and Shaanxi provinces in northwest China.

"We were at a temporary office of the local government and all of a sudden, everything in the room began rocking back and forth," said a CCTV reporter in Qingchuan. "The computer almost slipped from the desk and tiles fell from the roof. Everyone panicked."

A store keeper in Mianyang City, south of Qingchuan, said his store creaked in the aftershock and everyone fled. "We couldn't even stand still," he said.

"I could feel the ground and the mountain were shaking in the tremor," said a CCTV reporter in Beichuan County, which suffered the most from the May 12 quake.

Xinhua reporter Hai Mingwei said a plastic water bottle, placed upside down on the floor standing air conditioner of his home in downtown Chengdu, fell in the aftershock. "Though thousands of aftershocks were felt since May 12, this is the first time the bottle fell," he said.

After the devastating quake, many locals have put bottles in their house as a "forecaster" of aftershocks.

The aftershock was said to have lasted for about a minute and many high-rises in Chengdu rocked slightly.

A Beijinger said he felt the aftershock, too, from his 25th floor office. Residents on lower floors did not feel the tremor.

The tremor was also felt in Xi'an, capital of the northwestern Shaanxi Province, where citizens fled homes and offices to seek shelter in open spaces.

A hotel worker in Shaanxi's Hanzhong City said she felt clearly the aftershock was strong and "next only to the May 12 quake".

About 40 minutes before the aftershock, local residents said the weather in Hanzhong City became overcast and high winds began to blow. Mobile communication was in failure for a while.

In Lueyang county of Hanzhong, the tremor caused a cave-in on a provincial highway and disrupted traffic, said the county's publicity official Chen Weiming.

Chen said no casualties had been reported, but some houses collapsed and landslides occurred.

Many fear the aftershock and subsequent landslides might hamper some 1,800 rescuers' trekking to blast away the landslide barrier of Tangjiashan quake lake on Sunday night, before it bursts and causes a flood.

Their earlier attempts to carry out the mission from helicopters were hampered by bad weather.

The Tangjiashan quake lake, which is in danger of bursting as water builds up in it, is one of the more than 30 such lakes in rivers blocked by landslides from the earthquake and thousands of aftershocks.

The lake is 3.2 km upstream from the Beichuan County seat, from which thousands of survivors have been evacuated since Wednesday.

Its barrier is in danger of bursting as the water level rose by nearly 2 meters on Saturday to 723 meters, only 29 meters below the lowest part of the barrier, which measured 752 meters high.

Nearly 8,000 aftershocks have been reported in Sichuan Province following the May 12 earthquake. The death toll has hit 62,664 as of Sunday, including 62,161 in Sichuan alone.

(Xinhua News Agency May 25, 2008)