BEIJING - The Ministry of Culture has launched a three-month campaign against Internet cafes open to minors, after three teen suspects were found hiding in one following the killing of a teacher.

The campaign will target businesses outside cities nationwide, with a focus on severe violations such as "allowing minors to use the service for a long time or stay overnight, with doors and windows closed to avoid being found," the ministry said in a statement released Tuesday.

Chinese regulations ban Internet cafes from receiving minors. While urban cafes mostly stay in line, many in outskirts and rural areas where supervision is slack choose profits over obedience.

The issue was exposed in central Hunan province as providing shelter to three students aged between 11 and 13 after they allegedly battered a teacher with sticks and choked her to death last month. They were detained by the police.

The campaign also aims to spot places failing to provide a clean and spacious environment for customers, vowing to punish owners by revoking their licenses in severe cases.