XI'AN, May 10 (Xinhuanet) -- Staff members of an Internet service chain in Xi'an, capital of Shaanxi Province in northwest China, resigned Saturday over retaliatory assaults they had suffered for barring minors.

    Local police said Sunday they have stepped in to investigate an assault that happened Friday night at the Sanfuwan Outlet of the Hongshulin Internet Cafe Chain, which staff said was among a series of attacks by young people at the cafe.

    One of the staff, surnamed Chen, said he stopped seven or eightteenagers about to enter on the morning of May 6 because some of them looked very young. Chen asked to see their identity cards to verify their age. The teenagers refused and threatened to beat anyone who "dared to check identity cards." They tried to force their way into the cafe but were stopped.

    Amid recent campaigns to crack down on illegal Internet cafes and to ban people under 18 from entering, Internet cafes in China have been ordered to check identity cards of guests before they are allowed in. Otherwise Internet cafes themselves will face harsh punishment varying from a fine to closure.

    According to Chen, a group of some 16 young people broke into the cafe on the night of May 7, two guarding the door and two taking over the reception desk and telephones to prevent reportingto the police. The rest began to beat and punch Chen, some striking him with aluminum rubbish bins and fire extinguishers. Security guards of the cafe were also beaten.

    In an interview with a local newspaper, Chen showed the injuresto his back, head and face. His nose bridge bone was almost broken.

    According to Chen's colleagues, it was not the first such retaliation assault at the outlet. In their resignation letter, they listed many beating cases because of stopping young people. Their bicycle tires were deliberately damaged many times. Some even launched an online assault to the cafe's server, cut the broadband line, input junk programs into computers and poured mineral water into displays.

    To tighten security at the cafe, the local police station helped the cafe employ four security guards in April, but it proved not enough to prevent such assaults.

    The police have started investigation into the case and vowed to track down those responsible, said Tian Yuming, a senior policeofficer.

    China has shut down more than 8,600 unlicensed Internet cafes for admitting juveniles since February. To bar minors from Internet cafes, local governments across China have been ordered not to approve any Internet cafe operations in residential areas or within 200 meters of primary and high schools.

    The Chinese government has launched a nationwide check on all Internet cafes from February to August to halt the entry of minorsand to prevent access to detrimental information through the Internet. Enditem