Multi-sensor chemical and radiation detectors will be installed at the entrance and inside every Olympic venue, and troops equipped for chemical attacks will be stationed around, security officers said yesterday.

All visitors would undergo checks to prevent terrorist attacks, Cao Dongxiang, a senior officer from the Beijing public security bureau in charge of Olympic venue security, said in a group interview.

He said security staff at the venues would include paramilitary police, civil police, security guards and volunteers.