|Romney advocated the use of "covert action" to bring about "regime change" in both Iran and Syria [Reuters]
Republican US presidential candidates have vowed to undertake "covert" operations against Iran and Syria, including assassination, sabotage and aid to opposition forces, if they are elected to the White House in next year's election.
Newt Gingrich, the former speaker of the US House of Representatives who is seen as the latest frontrunner for the Republican nomination to take on current US President Barack Obama in November 2012, said that he would use "covert capability" to bring about "regime replacement" in Tehran.
Speaking to the Republican Jewish Coalition on Wednesday, the candidates redoubled their very public calls for tougher action against governments deemed to be hostile to US interests in the Middle East.
Gingrich said Washington should work towards "replacing" Bashar al-Assad, the Syrian president, and "do everything we can, indirectly and covertly - but without American forces - to help" the opposition overthrow his government.
On Iran, Gingrich said that under his administration the US would focus on "covertly sabotag[ing]" Iranian oil facilities "every day".
Mitt Romney, the former governor of Massachusetts who recently lost the mantle of frontrunner to Gingrich, called for Washington to secretly aid opposition forces in Iran.
"We should also have covert and overt activities to encourage voices of dissent within the country. Ultimately regime change is what's going to be necessary in that setting," he told the group.
Rick Santorum, a former senator who has fallen back in the polls for the nomination, backed similar calls for covert action against Iran.
"We need to say very clearly that we will be conducting covert activity to do everything we can to stop their nuclear programme. And that means using covert activity like may have occurred at [an Iranian] missile site," he said.
"With respect to covert activity, we need to be very clear: any foreign scientists working in Iran on this nuclear programme will be termed an enemy combatant and will be subject - like any other enemy combatant, like Osama bin Laden - to being taken out by the United States government as a threat to this country," he said.
Gingrich made similar calls at a November 12 debate, saying that the US should work towards killing Iranian nuclear scientists and disrupting Tehran's suspected nuclear weapons programme, "all of it covertly, all of it deniable".
Romney said that the US should also undertake "covert actions within Syria, to get regime change there".
"There are people in the military that are shifting over, that are becoming part of the rebel effort. We should support those efforts," he said.
Rick Perry, the governor of Texas, suggested at a debate in late November that the US should use "overt, covert [means and] economic sanctions" to put pressure on Assad in Syria.
Obama slammed on Israel
The White House hopefuls all also severely criticised President Obama's policy towards Israel, arguing that he was undermining the state's security, setting back peace efforts in the region and not acting harshly enough on Iran.
They accused Obama and his administration of placing undue pressure on Israel to return to the negotiating table with the Palestinians.
"This one-sided, continuing pressure that says it's always Israel's fault - no matter how bad the other side is - has got to stop," said Gingrich.
"President Obama has immeasurably set back the prospect of peace in the Middle East," charged Romney.
Romney won cheers from the crowd when he declared that Mahmoud Ahmadinejad, the Iranian president, "should be indicted for the crime of incitement to genocide" over his past anti-Israel remarks.
Gingrich, meanwhile, accused Obama of having called on Israel to "adopt indefensible borders," having "insulted" Benjamin Netanyahu, the Israeli prime minister, and being "timid and weak in the face of the existential threat that Israel faces from Iran".
Nita Lowey, the top Democrat on a US congressional committee that disburses foreign aid, called Romney's criticism
of Obama "shameful", saying US-Israel security ties were "broader and deeper than ever before".