More than 4,000 gambling machines were destroyed by Shanghai police on Wednesday.

Police seized the gambling machines during a campaign against game centers. More than 120 unlicensed sites were shut down and 420 illegal operators were investigated.

The police action was, in part, a bid to stop teenagers using them during the summer holidays.

“Any operator who runs gambling machines will be banned from doing business for a lifetime,” said Zhuang Liqiang, a spokesman for Shanghai police.

Shanghai Municipal Association of Culture and Entertainment Industry appealed to managers of gaming centers to operate in accordance with the law and refuse to serve teenage customers.