Romney says he understands the former House Speaker "must be very angry," but he's not sure why.
The former Massachusetts governor says he wishes Gingrich well and that there's still a long road ahead in the campaign for the Republican presidential nomination.
Romney says Gingrich may be lashing out because the former House Speaker has dropped so far in the Iowa polls.
Polls indicate Gingrich has gone from being the frontrunner in the Iowa caucuses to falling out of the top three.
He has blamed his fall on negative ads against him run by a political action committee that supports Romney.
Romney says he doesn't have control over ads put out by the independent PAC, and that at some point, Gingrich has to take some personal responsibility.
Romney said he couldn't predict who will win today's vote.