A nurse and a soldier help a patient to cross a bridge in the city of Beichuan, about 150km (93 miles) north of Chengdu, in Sichuan province, May 16, 2008.

Soldiers wear facemasks in the rubble of a chemical factory in Shifang, Sichuan province May 16, 2008.

Volunteers carry a survivor from the ruins of a collapsed apartment block in the city of Beichuan, located around 150 km north of Chengdu, in Sichuan Province May 16, 2008. China struggled to bury its dead and help tens of thousands of injured and homeless on Friday when a powerful aftershock brought new havoc four days after an earthquake thought to have killed more than 50,000.