Create a folder using code igniter?

[eluser]JasonS[/eluser]
I can create files. But how do I create folder?

I need to create the following.

/root/cities/cityname/
/root/cities/cityname/images/

I have had a look at the file helper class but cannot see how I can use it to create folder. Does codeigniter have a built in function for this?

How would I edit and delete there folders along with their content.