BEIJING -- Seven people have been detained after they were found to have disturbed the public order in a Chinese Super League (CSL) game, according to a statement released by Qingdao police on Friday.

The Qingdao police launched an investigation after several fans reportedly attacked match officials in the CSL game between Qingdao Hainiu and Nantong Zhiyun last Friday in Qingdao.

18 people were arrested, and seven of them were detained and given one-year stadium bans, the Qingdao police statement wrote.

According to a statement issued by the Chinese Football Association (CFA) on Tuesday, during the game, the home fans pelted the match officials twice with items, including one water bottle which hit the referee on the chest.

When the match officials drove off after the game, some fans attacked them with items such as water bottles, according to the CFA statement.

Chinese football's governing body has ordered the Qingdao side to play their next two home games behind closed doors as a punishment.