Roll back or revert entire svn repository to an older revision

I messed up on my SVN repository and now need to revert the entire repository from revision 28 to 24 and don't want to deal with diffs or conflicts. Is there a quick and simple way to do this? I've been able to revert back single files before fine with the merge command - but in this instance it wants to add all of the files back into the repository from revision 28 when all I really want to do is delete them.

I am using the command line on a linux box (bash).

Thanks

EDIT

Thanks for all of the help! I fixed it by:

svnadmin create /svnroot/<repo>.fixed
svnadmin dump -r 1:24 /svnroot/<repo> --incremental > dump.svn
svnadmin load /svnroot/<repo>.fixed < dump.svn

Then putting the old repo in a backup location and moving the repo.fixed to repo.

Thanks again!