Republican presidential candidates are lashing out at Iran, promising a pro-Israel group they will not hesitate to use America's military might against Tehran.

Former Senator Rick Santorum, former Massachusetts Governor Mitt Romney and former speaker of the House of Representatives Newt Gingrich spoke to the American Israel Public Affairs Committee Tuesday, as Americans in 10 states went to the polls to vote in the Super Tuesday primaries.

Santorum called for the United States to give Iran a “clear ultimatum” to dismantle its nuclear facilities. And he said if Iran fails to comply, the U.S. should “tear them down ourselves.”

Santorum told the pro-Israel political affairs group a nuclear Iran is a “threat to freedom loving people around the world” and that if Iran gets nuclear weapons, it will serve as a shield, protecting radical regimes and terrorists around the world.

Romney, speaking by a video link, accused Iran of pursuing nuclear weapons to “hold hostage the entire planet,” and said in a reference to enemies of Israel ” that placating jihadists will never result in peace.”

He said the “only thing respected by thugs and tyrants is our resolve backed our power and our readiness to use it,” promising to place “multiple aircraft carriers and warships at Iran's door.”

Gingrich, also speaking by video link, warned the U.S. cannot keep talking while the Iranians keep developing their nuclear program, saying “the red line is now.” He said that, if elected, he would adopt a strategy to replace the Iranian government by every means short of war.

Gingrich also promised to move the U.S. embassy from Tel Aviv to Jerusalem as a recognition of Israeli sovereignty over the divided city, and a U.S. energy policy that would ensure no U.S. president would ever again have “bow to a Saudi king.”

All three also accused President Barack Obama of turning his back on Israel, and chided administration officials for suggesting Iran would not use a nuclear weapon.

Santorum said there is nothing in the rhetoric from Iran to suggest the country is being run by “rational actors.”

Administration officials have denied the accusations that they do not fully support Israel saying cooperation between Israel and the U.S. in a variety of civil and military affairs has never been higher.