Huckabee told Breitbart on Sunday that President Barack Obama is marching the Israelis to "the door of the oven" -- a reference to the Holocaust -- by agreeing to a nuclear deal with Iran.
"Comments like this are offensive and they have no place in our political dialogue," Clinton said during a press availability in Iowa.
"It should be repudiated by every person of good faith and concern about the necessity to keep our political dialogue about the facts and within suitable boundaries," Clinton added.
Huckabee responded to Clinton's comments in a statement later Monday, saying, "Hillary Clinton came out of hiding today to attack my comments on Iran, calling them unacceptable, but what's truly unacceptable is a mushroom cloud over Israel."
He continued: "How many murdered Israelis will it take for Hillary to express as much outrage at Iran as she did at my defense of Israel?"
Unlike some Republican presidential candidates, Clinton has a personal relationship with Huckabee, who served as governor of Arkansas immediately after her husband, former President Bill Clinton, held the same office.
Clinton described their current relationship as "cordial."
Other Democrats have also slammed the remark.
"The particular comments of Mr. Huckabee are I think part of just a general pattern that we've seen that is, would be, considered ridiculous if it weren't so sad," Obama said during a press conference in Addis Ababa, Ethiopia.
Former Maryland Gov. Martin O'Malley, a Democrat challenging Clinton for the nomination, tweeted Monday that Huckabee's comments were "offensive & overlook this reality: Rep. policies have led us into 12yrs of conflict."
Huckabee has stood by his comments, including tweeting a graphic of the quote on Sunday.
The former governor also released a statement on Monday that stood by his remark and blamed the president for not taking the Iranians seriously.
"What's 'ridiculous and sad' is that President Obama does not take Iran's repeated threats seriously. For decades, Iranian leaders have pledged to 'destroy,' 'annihilate,' and 'wipe Israel off the map' with a 'big Holocaust,'" Huckabee said in a statement
Monday just hours after Obama spoke. "'Never again' will be the policy of my administration and I will stand with our ally Israel to prevent the terrorists in Tehran from achieving their own stated goal of another Holocaust."