OSAKA (Kyodo) -- The abuse of a sedative-laced vape liquid called "zombie cigarettes" has been increasing among youths in southern Japan, with investigative authorities stepping up vigilance against its potential spread nationwide.

By the end of September, 10 people, mostly in their teens and 20s, had been arrested in Okinawa Prefecture for possessing etomidate. In May, the Japanese government designated the substance, which is known to depress cerebellar neuronal activity essential for body coordination, as a prohibited drug.

In October, police arrested Yuto Agarie, the leader of a drug trafficking syndicate, for allegedly storing some 63.84 grams of etomidate-containing liquid at home in Urasoe with the intent to sell, they said Thursday. The local police suspect the group was the main supplier of the drug in the prefecture.

Used commonly in anesthesia induction for surgeries overseas, abuse of the drug can result in loss of consciousness or control of the body as well as spasms in the hands and legs. The Japanese government has banned the use, possession and import of the substance in principle.

The drug is advertised on secure messaging apps and has been spread via social media, investigative sources said. In many cases, etomidate is inhaled from an electronic cigarette or vape device, coming in flavored or unflavored varieties.

In August and September, three Chinese men in their 20s living near Tokyo were arrested for allegedly smuggling around 100 grams of etomidate from India via Singapore.

According to the health ministry's Narcotics Control Department, they are suspected of receiving orders via social media, liquefying the powdered substance, packing it in cartridges, and repeatedly selling it in person in the Tokyo metropolitan area.

The U.N. Office on Drugs and Crime reported in March that etomidate and its analogues have most notably been detected on illicit drug markets in East and Southeast Asia, including China, in recent years.

"We initially thought it was spread locally (in Japan) but subsequent investigations have shown that a market for etomidate has started to emerge in the country as well," an investigative source said.