The recent arrest of Mainland people sneaking into Hong Kong is said to be just the tip of the iceberg as authorities claim an average of 300 mainland women cross over from Shenzhen into the Special Administrative Region every week to to work as prostitutes.

The statement comes after the the 6th regiment of the Chinese national border police broke up a sophisticated operation that saw mainland suspects colluding with their Hong Kong counterparts in order to secretly ferry mainland women to cross the border in order to work as sex workers in the former British colony.

Eight suspects were arrested in Shenzhen’s Bao’an District on June 26 after a month-long investigation. Two men, Shu and Zhang, were named as the ringleaders.

Reports call the men “snakeheads”, a colloquial term used to describe human traffickers. However, reports don’t make it clear if the women were coerced into working as prostitutes.