"We have all the grounds to impose restrictions," the watchdog's chief, Sergei Dankvert, told Russian media Interfax.
He said quite a few instances of the use of ractopamine had been discovered in pork production in those countries.
"We're inviting the Brazilian and Canadian veterinary services to hold consultations, which could result in a decision to either limit supplies or to work more on guaranteeing the safety of the supplies," Dankvert said.
"Those guarantees that the veterinary services of those countries have already provided are not to our satisfaction as the violations continue," he said. Dankvert said the consultations would have to be held this week.
The Federal Service said in a statement that it had placed meat from Canadian enterprise Olymel (T 147) under heightened laboratory surveillance after a consignment of boneless pork containing E.coli was found.
The Service also stated it had warned the Canadian state veterinary service that such violations were inadmissible.