Suncor Energy, more than a week after launching an investigation into a cybersecurity incident, confirmed that an unauthorized party breached its IT network on or around June 21, the company said in a statement Thursday.

The energy giant based in Calgary, Canada said it has largely resolved disruptions at its Petro-Canada subsidiary, which includes more than 1,500 retail gas stations. The hackers gained access to basic information of Petro-Points members, which the company is notifying along with appropriate privacy regulators.

The company did not disclose how many customers were involved, but said it will notify customers if it finds out additional data was accessed. 

Suncor, the largest integrated energy firm in Canada, said the hack has not impacted the safety and reliability of its field operations.

Suncor originally disclosed the incident on June 25, and warned that Petro-Canada gas stations and some supplier payments would be disrupted. Customers were unable to make credit and debit card purchases at many of these retail locations and car wash locations were disrupted as well. 

Canadian authorities previously warned that state-linked threat actors were targeting the Canadian oil and gas sector for attacks in connection with the government’s support for Ukraine.