While many players believe winning prizes — often stuffed toys — from the machines is a matter of skill, they are actually games of chance, according to authorities in the southern American country.

On Wednesday, Rio de Janeiro police carried out 16 search warrants targeting claw machine operations while colleagues in the southern state of Santa Catarina carried out three more, The Independent reports.

Police in Rio say that because the claw machines are designed to let go of prizes until a certain amount of money has been deposited, they are effectively unlicensed gambling machines.

They also believe that some of the machines are linked to organised crime groups.