An investigation is under way into a number of targeted attacks on sex workers, mainly in the Dublin area.
Gardaí say seven attacks have taken place on sex workers advertising services on online sites since the middle of October.
On each occasion, an online appointment is made but when the parties involved meet, the sex worker is attacked and robbed by a number of men.
Gardaí say the motive for the attacks appears to be monetary gain, and violence has been used.
They said the attacks, which have targeted both male and female sex workers, have been terrifying incidents for the injured parties.
In a statement, gardaí said they are treating the victims with the "utmost sensitivity and confidentiality".
Investigations into the attacks are described as being at "an advanced stage".
Gardaí are appealing to anyone with information on the attacks to contact the Garda Confidential line on 1800-666111 or any garda station.
A list of victim support groups are available through the garda website