BEIJING - Chinese police knocked out 20 mafia-like organizations and 121 triad gangs, and seized 1,395 suspects in 689 criminal cases in a nationwide crackdown that started on Sept 16, a senior official of the Ministry of Public Security said on Tuesday.

Police in Beijing, Shanxi, Liaoning and another eight provinces launched raids that ended up with the arrests and dismantlement of a number of gangs that greatly disturbed social stability, market order and people's lives, said Liao Jinrong, deputy director of the criminal investigation bureau under the ministry.

In earlier crackdowns, police across the country smashed nearly 300 triad gangs, and detained nearly 2,200 suspects involved in gambling, extortion, intimidation or intentional injury.

Some criminal gangs were found manipulating the markets, controlling entertainment venues and provoking conflicts. Others used violence to collect debts and charged protection fees, according to Liao.

Some gang bosses even obtained a seat in a local people's congress, Liao said, citing a case in Benxi, Liaoning province.

Yuan Chengjia, who was a deputy to the Benxi people's congress, amassed a fortune of more than 2 billion yuan ($314 million) by running a mafia-like gang. His gangsters have been detained on suspicion of disturbing social order and intentional injury.

In October, Hunan police smashed one mafia-like 30-member gang in Chenzhou city, headed by Chen Xiaoqing. The organization was involved in intentional homicide, extortion and kidnapping, as well as drug-trafficking, which resulted in seven deaths and 10 severe injuries.

"Many people dare not provide clues to police or testify in court for fear of revenge," Liao said.

Moreover, some government officers, especially those from law enforcement, taxation as well as commercial authorities were found to be providing a "protective umbrella" to these gangs, he said.

"But no matter which official is involved, we won't tolerate that and will dig them out," he said.

Meanwhile, police will continue to collaborate with other departments to form a long-term working mechanism.

In the past five years, police across China have smashed a total of 2,174 mafia-like gangs and seized 4,273 firearms.

So far, the national anti-triads office has received more than 600 tips on its micro blog, and police are working on some important clues.

"Lax supervision of some government agencies provided a breeding ground for the gang crimes," Dai Peng, dean of criminal investigation department of the Chinese People's Public Security University, told China Daily, adding some officials have been corrupted by the gangs and provided shelter to them.