Key North Korean Web sites shut down for hours before recovering accessibility on Tuesday possibly due to a cyberattack, a source said.

The Web sites of North Korea's two key official news outlets -- Rodong Sinmun and Korean Central News Agency -- had been inaccessible from Tuesday morning before restoring connectivity at around 5:00 p.m. that same day.

They were the only North Korean Web sites that went down during the outage, with the country's other official Internet sites operating normally during the time.

One source well versed in North Korean affairs said "The Internet inaccessibility to Rodong Sinmun lasted from morning to 5:00 p.m. and there's a possibility that North Korea's Internet network might have sustained a cyber attack."

A group of main official North Korean Web sites went down for days in June last year although the reason of the Internet disruption remains unknown. (Yonhap)