Washington - Republican presidential candidate Mike Huckabee is likening the agreement on an Iranian nuclear deal to "marching the Israelis to the door of the oven", reference to the Holocaust.The former Arkansas governor made the tweet on Sunday, a day after first making the comparison when denouncing President Barack Obama for his role in the agreement reached on July 14 by the United States and five other world powers with Tehran.Responding, Democratic National Committee chairperson Debbie Wasserman Schultz said Huckabee's statement was "grossly irresponsible" and called on him to apologise.But a Huckabee spokesperson said on Sunday his comments reflect a longstanding position that "the Iran deal is a bad deal, bad for America and bad for Israel". Huckabee's tweet called on Congress to reject the nuclear deal."This president's foreign policy is the most feckless in American history," Huckabee said in an interview with Breitbart News broadcast on Sirius/XM radio Saturday. "He's so naive he would trust the Iranians and he would take the Israelis and basically march them to the door of the oven."Huckabee said that "this Iran deal should be rejected by both Democrats and Republicans"."We forget Iranians have never kept a deal in 36 years under the ayatollah. There's no reason to think they will suddenly start doing it."Huckabee said about the deal: "I read the entire thing. We gave away the whole farm. It's got to be stopped."Huckabee's comments come as the Republican presidential candidates struggle to break through with 16 presidential candidates already in the Republican field, and one of those, New York businessman Donald Trump, getting more attention than most.