BEIJING (AFP) - Chinese police have detained five people including a young couple over a sex tape shot in a Beijing clothing store which went viral in China, media reports said Sunday.

Those detained include the couple suspected of shooting the video - showing a mostly clothed man and a naked woman apparently having sex - in the changing room of a Uniqlo store in the capital.

The clip rapidly spread on China's Twitter-like Weibo and mobile messaging service WeChat, with scores of people taking selfies outside the outlet, some mimicking the poses seen in the footage.

Police held the couple on Wednesday night, just hours after the footage went viral, media said Sunday, citing an earlier report by state-run broadcaster Beijing Television.

"Five people were taken away by police including the man and woman who played the main role," the channel said in a report broadcast late last week.

"The police investigation has two main parts: who published this unsavoury video, and was it an example of hype by the business (Uniqlo)," it added.

China's online regulator the Cyberspace Administration of China (CAC) said late Wednesday that distributing the footage was "against socialist core values".

The CAC ordered senior managers of Weibo's operator Sina and Tencent, owner of WeChat, to cooperate in an investigation, the agency said in a statement.

China's Communist Party oversees a vast censorship system - dubbed the Great Firewall - that aggressively blocks sites or snuffs out content and commentary that is pornographic, violent or deemed politically sensitive.

Popular social networking sites such as Facebook and Twitter are inaccessible in the country, as is YouTube.