Video-sharing website YouTube has come under attack with hundreds of pornographic videos being uploaded onto its site.
The sexually explicit videos and inappropriate material were uploaded under the names of famous teenage celebrities like Hannah Montana and Jonas Brothers.
Many of the videos uploaded first started with footage of children's videos, and then continued on to adults performing graphic sex acts.
In one video titled 'Jonas Brother Live On Stage', a user posted a comment saying: "I'm 12 years old and what is this?"
Under other uploaded videos, online users posted comments such as: "Take the tags off, you'll get us caught."
Another said: "Your gonna kill us all!"
The raid on the website has shown how easy it is to upload porn onto a site, which is viewed by millions of people on a daily basis.
And as the videos were being uploaded, many viewers added them to their favourites and rated them highly.
One of the users believed to have uploaded the pornographic material videos was 21-year-old Flonty from Germany.
"I did it because YouTube keeps deleting music. It was part of a 4Chan raid," the BBC quoted him as saying.
4Chan is a bulletin board focusing on Japanese manga and anime, but some of its more extreme sections have been described on online message boards as "sick" and "horrifying stuff".
"Anything and everything can, and usually does, happen here. We have our very own unique culture, and there is no group quite like us anywhere out there," he said.
Flonty was asked if he was concerned that children could freely watch such inappropriate material on YouTube.
"Children will find inappropriate material around the internet anyway," he replied.
"This kind of raid showed how easy it is to upload porn to a website that millions of people browse on a daily basis," he added.
YouTube owner Google said that it was aware and addressing the problem.
"We are aware of the slew of pornographic videos that were uploaded," Google spokesman Scott Rubin said.
"We are addressing them as we would any video that violates our community guidelines.
"In addition, any account we discover that has been set up specifically to attack YouTube will be disabled," he added.