The personal information of about 20,000 Air Canada customers may have been compromised after a breach in the airline's mobile app and officials have locked down all user accounts until passwords can be changed.

The airline says unusual login activity was detected between August 22nd and 24th, which prompted it to lock down about 1.7 million accounts.

Air Canada posted a notice to app users on its website on Wednesday asking people to reset their passwords as a precaution.

Officials say immediate action was taken to block the hacking attempt and that ‘additional protocols to protect against further unauthorized attempts’ were implemented following the data breach.

Air Canada says credit card information is protected by encryption but that information included in about 20,000 user profiles may have been improperly accessed.

On August 29, the airline started sending emails to customers who may have been impacted with instructions on how to reset their accounts.

The breach affected about one percent of the app’s users and some passengers at the Calgary Airport said they are concerned.

“This is definitely scary when you have your personal info on those apps and put all your passport information or if you’re travelling internationally or social security or anything like that, it’s kind of scary to think about because there’s a lot of fraud that goes on these days,” said Raj Desai.

“We always have concerns, we don’t use apps a lot because of that reason, we’re concerned about privacy,” said Kevin Bailey.

Sharon Polsky is the President of the Privacy and Access Council of Canada and says she is not surprised by the data breach.

“It used to be a matter of if there would be a breach, it’s now a matter of when. It’s inevitable because programs, systems, computers, apps are all created by fallible people and they’re not perfect,” she said. “They locked everything down and have asked their account holders to renew their passwords and they’ve also required stronger passwords to be used now so it’s good that they’ve increased the security from that side but we still don’t know quite what information has been breached, who had access to it. We have been assured, though, that the financial information was encrypted and is secure and other information, it seems, might not have been encrypted and it’s a concern because we’re all encouraged to use the apps and, as a convenience, to put all of our information in them from our passport information to our address to our birthdate so that it’s available just at our fingertips. Unfortunately when it’s not properly protected, things can happen and it’s up to each user to try and figure out what happened and how to recover from it.”

The airline says some users may experience delays while trying to change passwords and suggests that people wait a few hours and try again.

For more information on how to reset accounts, click HERE.