A Canadian airline announced on Monday that personal information of some passengers was exposed in a cybersecurity breach earlier this year, although payment data was not compromised.

The company reported detecting suspicious activity on June 13 and later determined that an “advanced criminal external actor” had gained unauthorized access to its systems.

Earlier this month, a ransomware attack on Collins Aerospace, a subsidiary of RTX, disrupted operations at major European airports, crippling check-in and baggage systems at well-known hubs such as Heathrow and Berlin airports in London.

WestJet clarified that the type of data exposed in the breach varied but could include names, contact details, travel information, and documents related to bookings. The attacker did not obtain credit card numbers, expiration dates, or card verification numbers during the breach.

The airline stated in a release that it has been working closely with law enforcement agencies including the FBI and the Canadian Centre for Cyber Security, and has notified relevant authorities including prosecutors in U.S. states where affected residents live.