A group of teenage drug traffickers and users have been apprehended, police said Friday.

The Seoul Metropolitan Police Agency said it arrested three teenage drug traffickers including an 18-year-old American and a 17-year-old ethnic Korean from the United States. Police also booked 15 drug users, including four students belonging to a university-affiliated language institute in Seoul.

Officers said the three traffickers smuggled in 20 grams of cocaine worth five million won in July and sold it to or shared it with Koreans who either study or had lived overseas. Police also confiscated 40 grams of cocaine worth 103 million won and 50 grams of marijuana worth five million won from the residence of one of the traffickers.

They sold the cocaine for 100,000 won a gram, police said.

Those rounded up used the drugs in Shinchon, Itaewon and Gangnam, police added. “It is not the first time that youngsters have been arrested for drug use,” an investigator said. “They seem to have had similar experiences overseas.”

Meanwhile, cases of drug use and smuggling are rising. Police apprehended a group of ethnic Koreans at Incheon International Airport in May who were attempting to bring in a large quantity of illegal drugs.