WASHINGTON (CNN) -- In a new TV ad airing in Iowa, Republican presidential candidate Mitt Romney stepped up his attacks on rival Mike Huckabee, this time accusing the former Arkansas governor of being soft on crime.

But some of the claims Romney makes in the ad about his own crime-fighting record have raised questions.

With the crucial Iowa caucuses a little more than two weeks away, the Romney ad, titled "Choice: Judgment," attempts to contrast his record as Massachusetts governor with Huckabee's in Arkansas.

With pictures of the two candidates on the screen, the ad's announcer says that "Romney got tough on drugs like meth" and that "he never pardoned a single criminal." Watch Romney's ad attacking Huckabee »

The announcer goes on to say Huckabee "granted 1,033 pardons and commutations, including 12 convicted murderers. Huckabee granted more clemencies than the previous three governors combined. Even reduced penalties for manufacturing methamphetamine."

The announcer closes with "on crime the difference is judgment."

Speaking to reporters Monday in Los Angeles, California, Huckabee disputed the ad, pointing to his record of carrying out the death penalty while governor as evidence that he was tough on crime. Massachusetts doesn't have the death penalty.

"The difference between us is that I did something he never had to do. I carried out the death penalty 16 times, more than any other governor in my state's history," Huckabee said.

The statistics cited in Romney's ad come from a recent Associated Press examination of Huckabee's record of commutations and pardons. Huckabee received more commutation and pardon requests than Romney did and rejected 78 percent of them, according to The Washington Post.

One commutation request Huckabee rejected as governor was that of convicted rapist Wayne DuMond. But Huckabee supported DuMond's early release, and the convict raped and murdered a woman in Missouri after his 1999 parole. The mother of DuMond's victim has vowed to campaign against Huckabee's candidacy.

Romney's claim he "got tough" on methamphetamine dealers is questionable since a proposal to stiffen sentences never passed the Massachusetts Legislature.

The former Arkansas governor also challenged Romney's assertion that Huckabee had "reduced" the punishment for manufacturing meth.

"With Huckabee way ahead among evangelical voters, Romney is doing his best to change the subject to crime and, in an earlier ad, illegal immigration," said Howard Kurtz, The Washington Post's media critic and host of CNN's "Reliable Sources." "Huckabee may have a hard time fighting back. He's got little money for TV, while Romney is spending millions."

The two candidates have been engaged in almost daily skirmishes over their records since Huckabee emerged as the front-runner in Iowa a few weeks ago, a position Romney had held. The Iowa caucuses will be held January 3.

Before the disagreement over crime, the two exchanged barbs over foreign policy.

In the current issue of Foreign Affairs magazine, Huckabee says, "American foreign policy needs to change its tone and attitude, open up, and reach out. The Bush administration's arrogant bunker mentality has been counterproductive at home and abroad."

That stance prompted Romney, on NBC's "Meet the Press" on Sunday, to call on Huckabee to apologize to President Bush for his remarks.

"I said, 'Well, did this come from Barack Obama or from Hillary Clinton? Did it come from John Edwards?' No, it was Gov. Huckabee," Romney told host Tim Russert. "The truth of the matter is this president has kept us safe these last six years and that has not been easy to do."

Huckabee said he didn't have anything for which to apologize.

"I didn't say the president was arrogant," Huckabee told CNN on Sunday. "One of my opponents has mistakenly, maybe purposefully, misstated my position on that. I've said the policies have been arrogant." E-mail to a friend

All About Mitt Romney • Mike Huckabee • Crime • Foreign Policy