Spokeswoman Camille Habel said warrants were executed but she did not elaborate.
One of the homes targeted was where police were recently photographed making an arrest related to an anti-radicalization operation.
Uniformed Mounties were spotted by TV cameras Tuesday removing boxes and computer equipment in St-Leonard, in east-end Montreal.
In mid-May, federal authorities arrested 10 young Montrealers who were suspected of wanting to join jihadist groups overseas.
They were released without charge after police confiscated their passports, but authorities noted that an investigation was ongoing.