Popular online reference website Wikipedia went down in several countries after the website was targeted by what it described as a "malicious attack". The server of the Wikimedia Foundation, which hosts the site, suffered a "massive" Distributed Denial of Service (DDoS) attack, the organization's German account said in a tweet late Friday.

In a separate statement the Wikimedia Foundation said that the attack on the encyclopedia - one of the world's most popular websites - was "ongoing" and teams were working to restore access. DDoS attacks often involve legions of zombie computers - machines infected with viruses and commanded to simultaneously visit a website. Such a massive onslaught of demand can overwhelm website computer servers, slowing service or knocking them offline.

Copyright Agence France-Presse, 2019