The Finnish Transport and Communications Agency's website was targeted in a denial of service (DoS) attack on Monday for the second time this month, the agency announced on X, formerly Twitter.
Traficom, its official name, said it suspects that Monday's attack was carried out by a Russian-based group called NoName, which made a similar attack on its website and on other Finnish agencies and organisations earlier this month.
Denial of service attacks occur when a website is flooded with traffic or prompted to send information that causes it to crash.
The agency said it would file a criminal report with police about the incident.
Traficom's cyber security centre website was hit by a DoS attack on 7 September, with the NoName group later claiming responsibility.
The same group has also said it was behind other DoS attacks on Finnish websites.