Drug traffickers are using people in vulnerable groups as drug smugglers, including the physically and mentally disabled, people with acute and chronic diseases and women who breast-feed their babies, an annual drug control report released on Monday shows.

Police detained more than 4,500 such people across the country last year for trafficking, most of them recruited by drug lords, according to the 2016 report on the drug situation in China, released by the Office of National Narcotics Control Commission, China's top anti-drug body.

Experts said minors often are used in drug smuggling and other crimes worldwide because, if caught, they may face much lighter punishment. The disabled and women with infants are seen as less likely to be searched or interrogated.

According to Wei Jie, a lawyer specializing in criminal cases at Jieqiang Law Firm in Beijing, under the Criminal Procedure Law, lactating women and people with disabilities and acute infectious diseases can apply for house arrest when suspected of committing crimes. The severely ill can be excused from appearing in court.

Liu Yuejin, deputy director of the commission, said the growing market for drugs in China has led to a greater drug inflow from overseas.

But the report also shows the number of new registered drug users under age 35 dropped last year by 19 percent from the previous year. Officials credited nationwide anti-drug education efforts.

The use of new substances, often made in a laboratory, present a new challenge, according to the report. Fentanyl, for example, is a synthetic opioid blamed for overdose deaths worldwide.

The national drug testing laboratory under the Ministry of Public Security found 22 new substances last year, according to the ministry.

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