NEW YORK - U.S. Senator Hillary Clinton, a Democrat, canceled her appearance at a demonstration against the president of Iran after learning Republican vice presidential candidate Sarah Palin will be there, according to media reports Thursday. A group of Jewish organizations had said both Ms. Palin and Mrs. Clinton would speak at the protest near the United Nations on Monday against Iranian President Mahmoud Ahmadinejad, considered a foe here because he has said Israel should be wiped off the map. But Ms. Clinton adviser Philippe Reines said the New York senator would not be attending. "(Palin's) attendance was news to us, and this was never billed to us as a partisan political event," he said. Ms. Clinton lost a hard-fought battle for her party's nomination to Sen. Barack Obama, but is now supporting the Democratic nominee for the November 4 U.S. presidential election. Campaigners for Alaska Gov. Palin and Republican presidential candidate Sen. John McCain reacted swiftly to Mrs. Clinton's decision. "Governor Palin believes that the danger of a nuclear Iran is greater than party or politics," said Tracey Schmitt, a spokeswoman for the McCain-Palin campaign. "She hopes that all parties can rally together in opposition to this grave threat." U.N. officials have said it was possible that McCain and Ms. Palin will show up on Tuesday on the sidelines of the first day of the U.N. General Assembly. This would give Ms. Palin a chance meet a few world leaders on the day President George W. Bush and one of his main foes, Iranian President Mahmoud Ahmadinejad, address the 192 U.N. member states. Although Ms. Palin, 44, has brought new energy to the McCain campaign and helped narrow Obama's lead in opinion polls before the November 4 U.S. presidential election, Democrats say the mother of five lacks the foreign policy experience a vice president should have. Iran denies Western allegations that it is seeking atomic weapons, but has refused to suspend sensitive parts of its nuclear program that could be used to make atom bomb fuel.