Most of them were between 12 and 20 years old. "They are so young that they don't really get punished," Johnny Petersson, head of the local police in Skärholmen, tells TT.
The most common drug being sold is cannabis, but amfetamin and cocaine have also been encountered.
The criminals are using threats and rewards like sweets, smaller sums of money or narcotics to get the youngsters to do the job, TT reports.
"Some of them look up to these criminals, and some are very scared of them," says Jonny Petersson.
"Maybe you get to deliver a sachet of cannabis a few times, and then when you don't want to do it anymore they threaten to beat you up or to report you to the police," says Petersson.
Police will now put another 25 officers on the case to try to stop the trade, Swedish Radio News reports.