Leaflets naming alleged drug dealers in Belfast have been circulated online and to homes in the city.
The letters naming people in the north and west of the city have reportedly been posted to homes as well as on social media.
One leaflet, headed up public notice and signed A.A.D, names alleged drug dealers in the Beechmount and Springfield areas and urges those named to come forward to the Republican movement.
It states: "Failure to do so will result on [sic] the severest punishment, even as far as execution! Take this as the only warning."
The other lists 42 individuals under the headline, ' North Belfast drug dealers'.
The PSNI said officers were aware of the leaflets and did not "tolerate any type of vigilante activity".
Inspector David McBride said: "Police are aware of leaflets which have reportedly been circulated on social media and in Belfast which contains a number of names.
"We do not discuss the security of any individual, however, if we receive information that a person's life may be at risk we will inform them accordingly. We never ignore anything which may put an individual at risk.
"The PSNI does not tolerate any type of vigilante activity and we would caution any individual or group against taking the law into their own hands.
"The PSNI is responsible for law enforcement in Northern Ireland - we are here to protect local people and we are proud to serve them.
"Police would appeal to the community to continue to support them in their efforts to keep the area safe for everyone. Anyone with information or concerns should contact police on 101."
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