At least 174 municipalities globally were exposed to ransomware attacks this year, global cybersecurity firm Kaspersky said on Tuesday.
The average amount of the ransom demands was over $1 million while the highest demand was $5.3 million, the company said in a press release.
Ransomware -- a kind of malware -- locks or limits using computers' hard drives until a ransom is paid to an illegal organization.
Kaspersky said long-term costs of these attacks are worse than these figures.
Fedor Sinitsyn, a security expert from Kaspersky, said: "When a city is attacked, it is necessary to conduct a case investigation and inspection and this adds additional costs."
The number of attacks to municipalities and its side institutions rose 60% this year versus the previous.
Ransomware attacks affect both the financial structure of municipalities and the social life of people by interrupting municipal services.
"Paying criminals is a short-term solution that gives them both financial gain and encourages them to demand money again in the future," Sinitsyn noted.