Hackers attacked one of Ukraine’s most popular online banks with a massive distributed denial-of-service (DDoS) attack, focusing primarily on a service that Ukrainians use to collect donations for the military.

According to Oleh Horokhovskyi, CEO of Monobank, the attack lasted from Friday evening to Monday morning and reached a total volume of 7.5 billion requests per second. Horokhovskyi described the scale of the attack as “untypical”.

He said the incident had not affected the bank’s operations, but noted that the company had worked with Ukraine’s security services and specialists from U.S. cloud computing company Amazon Web Services to stem the flood of junk Internet traffic.

In a previous DDoS attack in January, Monobank faced 580 million junk service requests in three days. The bank only serves its customers through a mobile app, making it an attractive target for hackers.

The goal of the latest attack, Horokhovskyi said, was to disrupt the service that Ukrainians often use to raise funds for the country’s armed forces. This service has made donating relatively easy for users – all they have to do is create a virtual wallet and share it directly to their Instagram story for others to donate.

Horokhovskyi said that since Ukraine’s surprise invasion of the Russian city of Kursk, Monobank’s customers have been collecting donations three times faster than before.

The “uninterrupted” donations through the platform over the past three years have likely angered enemies and prompted them to try to hack the service “at any cost,” he added.

Monobank suggested that Russia was probably behind the attack, but did not provide any evidence. Horokhovskyi had previously described the bank as “one of the most frequently attacked” IT targets in Ukraine.

Another Ukrainian service – EasyWay, which provides information on public transport across Ukraine – announced on Monday that it had been the target of a DDoS attack and warned that it could affect its operations. EasyWay did not attribute the attack to any particular hacker group.

Russian services are also suffering from DDoS attacks, which often originate from Ukraine. Earlier this month, anonymous hackers attacked government and corporate websites and critical infrastructure services in Russia’s Kursk region following Ukraine’s invasion.

In July, several major Russian banks confirmed that they had suffered allegedly “foreign-planned” DDoS attacks that temporarily paralyzed their mobile apps and websites.

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