London, May 14 (IANS): Friday's global cyber-attack has affected more than 200,000 victims in 150 countries, Europol chief Rob Wainwright said on Sunday.

"The latest count is over 200,000 victims in at least 150 countries. Many of those victims will be businesses, including large corporations. The global reach is unprecedented," BBC quoted Wainwright as saying in an interview with Britain's ITV.

Wainwright said he was concerned that the numbers of those affected would continue to rise when people returned to work on Monday morning.

"We're in the face of an escalating threat, the numbers are going up," he said, and added that the current attack was unprecedented.

"We are running around 200 global operations against cyber crime each year but we've never seen anything like this," he added.

However, Wainwright said so far "remarkably few" payments had been made by the victims of the attack.

Friday's attack was the latest in the growing menace of ransomware in which hackers deliver files to computers that automatically encrypt their data, making it unusable until a ransom is paid.

The latest malware, called WannaCrypt or WannaCry, is spread by taking advantage of a Windows vulnerability that Microsoft released a security patch for in March. But computers and networks that didn't update their systems remained at risk.

Russia and Britain were among the worst-hit countries by the attack.

Security experts have warned that another attack is imminent, most likely on Monday, and could be unstoppable.