An air-raid siren was sounded at 10 a.m. Thursday in Chongqing to commemorate the victims of the Japanese bombing 60 years ago.

On June 5, 1941, Japanese air force flew more than 20 sorties, bombing the city for three hours.

About 2,500 residents, who hid in a tunnel in central Chongqing, were suffocated to death in the bombing.

With flowers and elegiac couplets, thousands of local people went to the site of the tunnel early Thursday morning to mourn for the victims.

Chongqing made the decision to sound an air-raid siren every June 5 since 1999.