US Republican presidential candidate Mitt Romney said Friday that the US "must lead the world in stopping Iran's genocidal regime from obtaining a nuclear weapons capability." Romney's comments came after Iranian President Mahmoud Ahmadinejad said Friday that Israel is a "tumor" that needs to be wiped out. The Republican presidential candidate reiterated remarks he made in a visit to Jerusalem in July, claiming: "We have seen the horrors of history. We will not stand by. We will not watch them play out again." "Ahmadinejad’s latest outrageous remarks are just another reminder of what is at stake," Romney stated. The comments by Ahmadinejad came at a rally marking Al-Quds Day (Jerusalem Day), an annual anti-Zionist event calling for Palestinian liberation.Republican congresswoman Ileana Ros-Lehtinen, chairwoman of the House Foreign Affairs Committee, used Ahmadinejad's statements to reiterate Romney's position that the administration of US President Barack Obama has failed to deter Iran's nuclear ambitions, putting Israel's existence in danger. Ros-Lehtinen said Friday that Ahmadinejad's "incendiary" comments were just another warning that "a fuse is burning."She stated that the Obama administration had failed in dealing with "rogue regimes," remarking, "I have many serious concerns about this administration's Iran policy. Obama's approach seems to be based on a complete misreading of the intentions of the ayatollahs... by wasting precious time, his policies have placed the security of the State of Israel in jeopardy. It's past time for a change in leadership in the White House." Congressman Paul Ryan, Romney's running mate, also referred to Iran at an election rally in Virginia, saying a Republican administration will pull out all the stops in order to protect America's allies across the world."Under president Romney our adversaries will think twice about challenging America and our allies because we believe in peace through strength," Ryan vowed.The Republican campaign's comments on Iran came amid increased speculation that Israel was planning a unilateral strike against the Islamic Republic's nuclear facilities, a move which the Obama administration has intimated they would see as premature. Washington has repeatedly stated in recent weeks that diplomatic efforts and sanctions aimed at preventing Iran from obtaining nuclear weapons have not run their course. US Defense Secretary Leon Panetta and chairman of the US military's Joint Chiefs of Staff Gen. Martin Dempsey also said last week that a unilateral Israeli strike "could delay but not destroy Iran’s nuclear capabilities.”Earlier Friday, US National Security Council spokesman Tommy Vietor was quoted by AFP as saying that the White House strongly condemns "the latest series of offensive and reprehensible comments by senior Iranian officials that are aimed at Israel. The entire international community should condemn this hateful and divisive rhetoric."