SEVASTOPOL, July 11. /TASS/. WannaCry ransomware attack was a "trial run" with the goal of sniffing out the vulnerability of various sectors and more large-scale attacks are anticipated, Russian Presidential Envoy for Information Security Cooperation Andrey Krutskikh said on Tuesday.

"For example, the latest WannaCry attack in 150 countries, it seemed that the damage was small, but this attack was a test. I can say beforehand that more serious attacks are expected," Krutskikh told the Infoforum held in Crimea’s Sevastopol on July 11-12.

On May 12, hackers tried to attack Windows OS computers across the world using a WannaCry ransomware. Most attempts at infecting computers were registered in Russia. Hackers asked for a bitcoin ransom payment ($600) to unlock infected computers. Some reports say that they had used a hacking tool developed by the US National Security Agency.

Last month, Deputy CEO of Russia’s top lender Sberbank Stanislav Kuznetsov, who oversees information security, also warned that more ransomware attacks could be carried out soon.