More than 420,000 houses collapsed in the Qingchuan County in southwest China after two fresh aftershocks hit the area on Tuesday afternoon, according to the local disaster relief headquarters.

A 5.4-magnitude aftershock hit Qingchuan in Sichuan Province at about 4:03 PM and another 5.7-magnitude tremor hit the neighboring Ningqiang in Shaanxi Province, according to the China National Seismological Network.

A total of 63 people were injured in Qingchuan alone, six of them critically, officials with the headquarters said.

The newly collapsed houses totaled 4.95 million square meters, adding to about a million houses which were already damaged or leveled in previous tremors.

In Qingchuan, a total of 15,453 people have been injured since the May 12 earthquake, including 1,654 who were in serious condition.

The new aftershocks have also engendered 146 new geological hazards including cracks and debris slides in the mountainous area, the headquarters said.

(Xinhua News Agency May 28, 2008)