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,” a reference to the Holocaust.

The former Arkansas governor made the tweet Sunday, a day after first making the comparison when denouncing President Barack Obama for his role in the agreement reached July 14 by the United States and five other world powers with Tehran.

Responding, Democratic National Committee Chairwoman Debbie Wasserman Schultz said Huckabee’s statement was “grossly irresponsible” and called on him to apologize.

But a Huckabee spokeswoman said 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.”

Obama, asked about the comments at a news conference in Addis Ababa, where he was meeting with Ethiopian officials, said they were part of a pattern of attacks by 2016 Republican presidential candidates that would be “considered ridiculous if it weren’t so sad.” He said such issues as the Iran nuclear deal deserve serious debate, not outlandish statements.

“It doesn’t help inform the American people,” Obama said.

Huckabee quickly responded, saying that “What’s ‘ridiculous and sad’ is that President Obama does not take Iran’s repeated threats seriously.”

In his initial remarks, 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.

Meanwhile, the head of the Republican Party said on Monday party candidates running for the White House in 2016 should vow not to run as independents, a move that could give Democrats the edge in the presidential race.

“I think our candidates should pledge not to run as a third party candidate,” Republican National Committee Chairman Reince Priebus told NBC News in an interview.

His comments come after real estate mogul and TV personality Donald Trump said recently he would consider his presidential bid as a third party candidate if the Republican Party didn’t treat him fairly, and accused the party of not supporting him.

Priebus said he was not worried about Republican candidates launching out on their own, and that the party’s contenders understood the importance of uniting to beat former Secretary of State Hillary Clinton, the Democratic Party’s presidential front-runner.

“I think everyone understands that. If Hillary Clinton’s going to get beat, she’s going to get beat by a Republican,” he told NBC on its “Today” program. “If our candidates want to win, then they’ll have to run as a Republican.”

Trump has broken ahead of the Republican field in recent polls even as he stirred controversy with his remarks about immigrants from Mexico, questioned US Senator John McCain’s war service and lobbed personal attacks against fellow Republican presidential candidates.

He led the pack in several polls released on Sunday. Reuters polling also showed Trump tied with former Florida Governor Jeb Bush as of July 24.