Mitt Romney and Rick Perry sparred over illegal immigration in the most intense exchange of the election season yet.

Perry dug up a story from 2006 accusing Romney of hiring a landscaping company that employed illegal immigrants — saying his tough stance on immigration is "the height of hypocrisy."

Romney responded by blaming it on the country, basically saying that it is hard to find contractors who don't hire illegals these days:

"Look, we went to the company and said, you can' have illegals working for your company — I'm running for office for Pete's sake, we can't have illegals."

But Romney barely gets through his answer before Perry interrupts: "Are you a liar?"

To which Romney fires back: "You have a problem with allowing people to finish speaking," Romney retorted, "and I suggest that if you want to be President of the United States you have to let both people speak."

Watch the whole video below via TPM: