Hundreds of YouTube channels have been hacked by security group OurMine, which is claiming it as "The biggest hack in YouTube history".

Videos of the compromised accounts display posts with titles that begin "#OurMine" and feature the description "Hey, it's OurMine, don't worry we are just testing your security, please contact us for more information".

Videos of Youtuber RomanAtwoodVlogs with altered titles and descriptions.

Contact details of the group then follow.