The pro-Russian hacker group NoName057(16) has claimed responsibility for the cyberattack on the websites of several Croatian institutions, according to a post on their website on the Telegram channel.

“It's been a while since we've visited Croatia and we decided to ‘remind’ ourselves,” the group said on their English-language website including notices showing that the websites of the Croatian Tax Administration and the Croatian National Bank were unavailable. The message was posted on Wednesday.

The group also announced its attacks on the X platform, but there has been no mention of the hacking of the Croatian institutions there.

According to data on the two social platforms, in recent days the group has crashed a number of websites in Ukraine, Austria, Belgium, Cyprus, Bulgaria and Romania.

According to organisations monitoring hacker attacks, NoName057(16) is a pro-Russian hacker group that first appeared in March 2022. Since then, according to the group's own claims, it has been attacking the websites of state institutions, media and private companies in Ukraine, Europe and the United States.

The websites of several Croatian institutions, including the Ministry of Finance, the Tax Administration, the Croatian National Bank and the Zagreb Stock Exchange, were the targets of cyberattacks on Wednesday, while the KBC Zagreb hospital was targeted on Thursday.