Image copyright AFP/Getty Images Image caption Police are investigating whether the video was a publicity stunt co-ordinated by Uniqlo, reports say

Police in Beijing have arrested five people over a sex tape filmed in a branch of the Uniqlo clothes shop, Chinese state media say.

A clip filmed in the dressing room of a Beijing store went viral on Chinese social media last week.

Media reports said the couple in the video were arrested on Wednesday, hours after the footage was published.

Part of the investigation will reportedly focus on whether the clip was a publicity stunt.

The clip quickly spread on Weibo, the Chinese social network, and on the mobile messaging service WeChat.

Image copyright AP Image caption Since the video was posted, people have been posing for selfies outside Uniqlo stores in China.

China's online regulator, the Cyberspace Administration of China (CAC), said that distributing the footage was "against socialist core values" and called for online operators to help with the investigation.

"The police investigation has two main parts: who published this unsavoury video, and was it an example of hype by the business," Beijing Television said.

China Daily reported that Uniqlo could face a fine of between 200,000 and one million yuan (£21,000-£103,000) and see its licence revoked if the video is found to be a publicity stunt.

Uniqlo, a Japanese-owned company, has not responded to the reports.