Image copyright AFP Image caption Police detained 67 people and shut down 12 venues, state media said

Police in China have launched a crackdown on the sex trade in Dongguan, following a state TV report on prostitution in the southern city.

Police arrested 67 people and shut down 12 venues, while two police chiefs were suspended, state media report.

Prostitution is illegal in China, but the sex trade is widespread.

One newspaper said that Guangdong province's Communist Party chief had called for "an extensive trawling-style crackdown on the entire city".

But the police action in Dongguan has sparked a strong reaction on social media in China, reports the BBC's Yuwen Wu, with many accusing state television of being "heartless" in targeting sex workers in the city.

Analysis Posters on social media have urged Dongguan to "stick it out" and "not to cry" and many claim: "We are all from Dongguan tonight." One post says: "There are many more important issues in China, such as the luxury hotels, and black brick factories, and you never see CCTV reporting those seriously, so why are they picking on something petty?" The famous blogger Wuyue Sanren is especially sympathetic to sex workers: "They are a vulnerable group in society, and if you want to expose this, you really should expose the root causes behind it, rather than just secretly recording dancing in the sex parlour to sensationalise the news." But there are some voices supporting the official action and CCTV too. One resident claiming to be from Dongguan points out that a crackdown on the city's sex industry is only proper.

Dongguan is sometimes called the "capital of sex" because of its reputation as a hub for the sex trade.

The investigative report by state broadcaster CCTV, which aired on Sunday, said that prostitution took place in several entertainment venues in Dongguan.

Covert footage in the report showed women lined up on stages at various venues, while managers discussed their fees for sexual services.

Hours after the report aired, police launched a major crackdown, with more than 6,000 officers investigating saunas and entertainment venues, state media reported.

According to some estimates, there are four to six million sex workers in China.

A BBC investigation in October found evidence of organised prostitution at independently run spas located inside a number of well known, Western-brand hotels.

Last year, a report by advocacy group Human Rights Watch (HRW) said that sex workers in China experienced abuse by police, including physical assault, arbitrary detentions and extortion.