The Federal Trade Commission (FTC) is probing whether Visa Inc. and Mastercard Inc. tokens for security restrict competitors to debit cards in online payments, The Wall Street Journal said Monday, citing people familiar with the topic.

According to the report, the FTC has focused on routing issues deriving from network security tokens in recent months. On the other side, it is not clear yet if this one is a new investigation or part of a previous one.

Last year, the United States Department of Justice said it was investigating Visa Inc.'s dealings with several financial-technology firms. According to the sources, this investigation is ongoing.