BEIJING, Jan. 22 -- Chinese customs authorities investigated 2,275 criminal smuggling cases in 2014, an increase of 10.4 percent from a year earlier, official data revealed on Thursday.

The cases involve 66.9 billion yuan (10.9 billion U.S. dollars), a year-on-year increase of 65.5 percent, the General Administration of Customs (GAC) said. Of the total, 170 major cases each involved tax evasion totaling more than 10 million yuan, 1.1 times more than that of 2013.

In 2014, the GAC stressed harsh checks and punishment on agricultural products, overseas waste and endangered animals and plants.

In a special campaign against the smuggling of agricultural products last year, the GAC had cracked 638 cases, involving nearly 38 billion yuan, GAC said.

In another special campaign against drug smuggling in 2014, Chinese customs authorities had cracked 471 cases and seized 4.4 tonnes of drugs in total.

For 2015, the GAC said it would continue cracking down on smuggling activities, especially on agricultural products, arms, drugs and waste from overseas.