Police in 10 provinces and cities along the Yangtze River have cracked down on 90 groups involved in illegal sand mining during the past nine months, the Ministry of Public Security said on Thursday.

They have uncovered 1,667 criminal cases related to illegal mining and seized over 1.79 billion yuan ($251 million) related to sand mining, 305 sand mining vessels and 2.88 million cubic meters of sand.

On Jan 11, the ministry launched a one-year campaign cracking down on illegal sand mining and deployed public security forces in the cities of Shanghai and Chongqing, as well as Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Sichuan, Guizhou and Yunnan provinces.

Due to huge profits realized from the critical building material, sand mining has become a key money maker for organized criminals.

Tang Wenfa, police chief of Yueyang, Hunan province, said such illegal activities could seriously disrupt public security.

"Illegal sand mining vessels were mainly active at night to avoid police, but they caused multiple boat accidents in the waterway," Tang said.

"The large-scale sand mining vessels can drill to a depth of 20 meters, which could alter a river's course and endanger protection works on both banks, causing the collapse of dams.

"Some local officials may even get involved in illegal sand mining, tempted by huge profits from criminals under "protective umbrellas", Tang said.

Yueyang is investigating over 100 tips in this regard, and six officials have been detained, he added.

Huang Ruixue, political commissar of the Criminal Investigation Bureau of the ministry, said that the police will rely on existing institutional mechanisms for fighting organized crime.

Cooperation among provinces and departments has achieved results.

Police and water resources departments in Hubei, harbor supervision departments and the Changjiang River Administration of Navigational Affairs shut down 39 illegal mining areas and dismantled 536 docks.

A group consisting of 50 people from Hubei, Hunan and Chongqing was also smashed by the joint law enforcement team, Huang said.