[ESS] Is there a way to continue using emacs while C-c C-r ess-eval-region is running?

[regcl]

C-c C-r, bound to ess-eval-region, locks emacs until the evaluation is complete.

This is annoying because my blocks of code take a long time to complete.

Is there a way to continue using emacs while C-c C-r ess-eval-region is running?

Using: GNU Emacs 24.0.93.1 & ess-12.04.

Thanks
regcl