How do I remove urine stains from under the rim of the toilet bowl?

I noticed that there is a strong urine stain in the bathroom and after inspecting, i noticed what appears to be urine (strong odor, yellow - brown stains) accumulated under the rim of the toilet bowl. I have no idea how it got there. I tried using a toilet bowl cleaner, but it didn't take a lot of it out. What can I do to remove the stain and urine?