More than 30 police officers have been detained, say reports
At least six district police chiefs in the Chinese city of Chongqing have been detained as part of a crackdown on criminal gangs.
They were being investigated on suspicion of giving "protective umbrellas" to gangs, said state media.
Local media reported the gangs were involved in illegal casinos, loan sharking and extortion.
The two-month investigation has already caught the long-standing former deputy head of Chongqing's police.
Wen Qiang, the once high-profile director of the Chongqing Municipal Judicial Bureau, was detained earlier this month alongside the head of the judicial bureau.
Wang Lijun, a top policeman know for being tough on gangs, has been brought in to Chongqing to oversee the continuing cleanup.
So far, 1,544 suspects have been investigated, including prominent business people, the China Daily reported.
Earlier this month, a government spokesman said more than 100 suspected gangsters had been detained in Chongqing alone and 14 gangs broken up.
Climate of fear
China Daily cited a senior police officer as saying 30 to 40 police officers had been detained in the city so far for involvement in crimes or for protecting gangs.
Three of the six district police chiefs were detained a few minutes before the opening of a meeting last week that was to focus on the anti-gang operation.
The local government has vowed to "uproot every protective umbrella for gangs", a phrase used to refer to corrupt officials or members of the judicial system.
Hong Kong's South China Morning Post said there was a climate of fear among the city's police forces, with staff working double shifts seeing their colleagues disappear into jail on a daily basis.
The wife of the deputy director of Yubei district police bureau committed suicide after her husband was detained for alleged involvement in a local gang that had monopolised the local pork market, China Daily said.
The paper also quoted an unnamed policewoman as saying she had never thought the campaign could go so far.