Shanghai, China's biggest city, is to purchase three police helicopters.

The helicopters will help to police traffic, assist in crime cases and respond to medical and other emergencies, according to the municipal Public Security Bureau.

They will be used to police nine preliminary Olympic football matches held in Shanghai in 2008, police said.

China has seven police helicopter fleets, three police airports and 20 police helicopters.

The first police helicopter in China was put into use in Wuhan, capital of central China's Hubei Province in 1994.

Zhengzhou, Shenzhen, Nanjing, Dalian and Sanmenxia also use police helicopters.

Source: Xinhua