North Korea disappeared from the internet for several hours on Friday and over the weekend as crucial servers inside the country were unreachable, log files and domain records obtained by NK News show.

The patterns of failing connectivity suggest that North Korea’s IT infrastructure may have been hit by a distributed denial-of-service (DDOS) attack, said cybersecurity researcher Junade Ali.

“The intermittent connection issues, coming in waves, alongside the complete router failure, indicate this may be a DDOS attack,” Ali told NK News. He explained that all email, web and Domain Name System (DNS) servers in the country were affected