Police in six European countries, as well as Canada and the United States, completed a joint operation to take control of Internet servers used to run and control a malware network known as "Emotet", authorities said in a statement.

Germany's BKA federal police agency said in a statement that "Emotet is currently seen as the most dangerous malware globally.

"The smashing of the Emotet infrastructure is a significant blow against international organised Internet crime."

German police said infections with Emotet had caused at least 14.5 million euro of damage in their country. Globally, Emotet linked damages cost about $2.5 billion, Ukrainian authorities said.

Ukraine's General Prosecutor said police had carried out raids in the eastern city of Kharkiv to seize computers used by the hackers. Authorities released photos showing piles of bank cards, cash, and a room with tangled computer equipment, but did not say if any arrests were made.