A Sina Weibo user uploaded images of a riot he says took place in Shenzhen’s Nanshan District yesterday. The user @吴俊南123456 says up to 50 riot police were called in after a vendor was beaten up by chengguan. However, no established local media outlet has yet confirmed the claims.

According to a round-up in Bannedbook.org, it started when a group of chengguan beat up a vendor and were then surrounded by over 1,000 angry members of the public.

Riot police were then allegedly sent in to restore order. Here are some of the images that were uploaded:

The vendor who was allegedly beaten up by chengguan. The vendor is said to have been from Xinjiang

The chengguan are surrounded by angry passers-by

The riot police arrive

If all these claims are true, it will be a step backward in two very important relationships: that between chengguan and the public and that between Xinjiangese and the Han locals in the places they migrate to.

This month, Guangzhou enacted rules stipulating that Chengguan must show basic courtesy to people they meet. This was aimed at improving the image of the notoriously hated and feared law enforcers.

After weekend’s deadly car crash in Tiananmen Square, Uighur suspects are being sought in connection with the case. It has even been suggested that it may have been a suicide attack by Islamic separatists.

There is always plenty of tension between the Han and the Uighur bubbling just below the surface, as became evident in the Urumqi riots of 2009.

Baishizhou is one of Shenzhen’s most diverse areas. It has been written about extensively by local anthropologist and China-hand Maryann O’Donnell.