Beijing  - Two courts in the south-western city of Chongqing on Monday opened the first trials of hundreds of people, including several top officials, accused of involvement in some of China's largest organized crime rings.

An official at Chongqing's Number 3 Intermediate People's Court told the German Press Agency dpa that the first trials were "still under way" on Monday afternoon, adding that the duration and the number of defendants were "secret."

State media said the first trials included 31 members of two mafia groups led by Yang Tianqing and Liu Zhongbing.

Chongqing police questioned more than 2,000 suspects in a six-month crackdown on organized crime, including 67 alleged gang leaders and 50 government officials.

The police formally arrested more than 600 suspects, while Chongqing state prosecutors had charged 263 people by the end of August.

Wen Qiang, the former director of the city's justice bureau, and a former deputy police chief were among those detained by police for questioning, earlier reports said.

The city escalated its campaign against organized crime after the murder of an 18-year-old soldier who was shot at his sentry post and robbed of his submachine gun by an unidentified attacker in March.

Chongqing was reportedly one of China's biggest centres for weapons' trafficking, while the gangs also controlled prostitution, gambling, drugs, entertainment and many local businesses, including one city bus company.

Some of the trials relate to offences dating back 10 years or more.

City courts also tried a major organized criminal gang last April, sentencing 19 people for convictions of murder, drug trafficking, robbery, illegal possession of firearms, and bribing police officers.

In an editorial on Monday, the official China Daily newspaper said the fact that many top officials were detained in Chongqing "points to the local government's resolve to fight organized crime."

The fact that members of the public provided thousands of tips to police, and were generally willing to identify themselves, showed that the 30 million residents of the Chongqing area "had enough of the gangs," the newspaper said.

It said the provision of "protective umbrellas" to the gangs by city government officials and police officers was a problem of China's "transition from a planned economy to a market one."

The Ministry of Public Security said prosecutors nationwide had charged more than 14,000 suspects in some 1,200 cases involving organized crime since 2006. (dpa)