TORONTO, July 24 (UPI) -- Self-service check-in kiosks at Toronto's Pearson International Airport are under scrutiny after several cases of identity-theft fraud.

Credit card operator Visa recently approached the Greater Toronto Airport Authority, which licenses the card readers, with concerns of "isolated" and "increased" instances of credit card fraud taking place among passengers swiping cards to obtain boarding passes, the Toronto Star reported Thursday.

There are about 150 terminals that allow passengers to bypass lines for ticket agent check-in, and 13 airlines make use of them. On Wednesday, in light of reports of the potential fraud risk, WestJet airline announced it was disabling the readers in its boarding areas, the Star said.

Scott Armstrong, a spokesman for the GTAA, told the newspaper passengers concerned with possible credit fraud had other options to check in, including swiping passports or drivers licenses, or simply typing in their names.

Neither Visa nor the GTAA have disclosed any details on alleged fraud or identity theft, the newspaper said.