Photo: ThePaper.cn

WUHAN, May 28 - A Chinese court on Monday sentenced two bosses of a mafia-like criminal gang to 20 years in prison for extorting money from sand-mining ships on the Yangtze River.

China issues licence for sand-mining ships in the Yangtze Rivers in order to prevent over-mining on the river.

The defendants, Liu Yang and Huang Huayu, led a gang of around 16 people providing protection to illegal sand-mining ships while extorting money from others on a section of the Yangtze River near Wuhan City, capital of central China's Hubei Province, the Wuhan Intermediate People's Court said.

The gang extorted more than 1.73 million yuan (270,000 U.S. dollars) from 2,381 ships from 2015, according to the court.

"The illegal activities have greatly damaged social security, navigation order, economic order and the environment on the river," said Wang Yan, of the court.

Another 14 gang members were sentenced to prison sentences between three and 11 years.