Shanghai police will intensify supervision of entertainment and recreation places across the city after a series of crackdowns on prostitution, gambling and drug-related businesses this year.

The Shanghai Public Security Bureau will target illegal activities at thousands of karaoke, dance, game and bath clubs across the city to create a better social environment for the coming World Expo, the police said over the weekend.

The police said the crackdown's aim was "to purify the society."

The police bureau has denied, however, that crimes related to prostitution, gambling and drug have become a big problem for the city.

"These phenomena are overall under control," said an officer in charge surnamed Zhou. "They haven't stood out as a main problem of the public security."

Zhou said the police bureau had given all 350 police stations across the city more responsibilities, including the intensified supervision on entertainment and recreation venues.

The police said they have finished dispatching 3,680 security guards to the city's 1,000 karaoke and dance clubs, a drive started two years ago to increase supervision, and will do the same at bathing clubs.

And about 100,000 employees of the entertainment places have been registered into the police's database.