Ukraine’s state-owned railway operator Ukrzaliznytsia said Monday that it was hit by a large-scale cyberattack.

The cyberattack affected online ticket sales, including via the mobile app, while trains continue to operate, according to the railway operator’s statement on its official Telegram channel.

Daryna Antoniuk, a journalist based in Ukraine, reported the disruption for The Record from Kyiv’s central station, writing that the capital’s main railway station was “unusually crowded on Monday morning, with dozens of people waiting in long lines to buy tickets for travel within Ukraine and abroad.”

In its announcement, Ukrzaliznytsia said (per a machine translation): “The enemy failed to do the key thing: train traffic is stable, they run clearly, without delays, and all operational processes of traffic are set up in a backup format.”

“As a last resort, if you do not have time to purchase a ticket through the ticket office, go directly to the train,” the operator told customers.