(Adds Larijani background) By Caren Bohan LEESBURG, Va., Oct 21 (Reuters) - U.S. Vice President Dick Cheney on Sunday described Iran as an obstacle to peace in the Middle East and said the world could not stand by and allow it to develop a nuclear weapon. Cheney's comments underscored a ratcheting up of U.S. rhetoric toward Tehran and came just days after President George W. Bush warned that a nuclear-armed Iran could lead to World War Three. "The Iranian regime needs to know that if it stays on its present course, the international community is prepared to impose serious consequences," Cheney told a forum organized by the Washington Institute for Near East Policy. "The United States joins other nations in sending a clear message: We will not allow Iran to have a nuclear weapon." "Our country and the entire international community cannot stand by as a terror-supporting state fulfills its most aggressive ambitions," he said. Cheney discussed Iran in a speech in which he emphasized the importance of continued U.S. engagement in the Middle East and said the United States seeks stability there but not the kind that "simply keeps a lid on" problems. U.S. Secretary of State Condoleezza Rice has recently returned from the Middle East where she has been trying to lay the groundwork for a conference on Middle East peace expected to take place in Annapolis, Maryland, in late November or early December. Cheney spoke in only broad terms about the goals of the peace effort, saying the conference would aim to "provide diplomatic support" to parties seeking a deal on Palestinian statehood and review progress on building Palestinian institutions. On Iran, he repeated Washington's criticism that it was interfering in Iraq, in addition to citing concern about its nuclear program. Iran rejects accusations it is seeking to develop a nuclear bomb, saying it wants nuclear technology for peaceful civilian purposes such as power generation, and has refused to heed U.N. Security Council demands to halt sensitive uranium enrichment. Cheney said progress toward a more stable and peaceful Middle East would depend on responsible conduct by countries in the region, such as respect for neighbors' sovereignty and compliance with international agreements. "If you apply all these measures it becomes immediately clear that the government of Iran falls far short and is a growing obstacle to peace in the Middle East," Cheney said. CRITICISM OF SYRIA Bush, who has insisted he wants a diplomatic solution to the Iranian issue, is pushing for a third round of U.N. sanctions against Iran. But he faces resistance from Russia, a veto-holding member of the U.N. Security Council which backed two sets of limited U.N. sanctions against Iran but has been cool to the idea of any tough new measures. Meanwhile, the resignation of Ali Larijani as Iran's chief nuclear negotiator, announced on Saturday, has been viewed by some analysts as a sign that Iranian President Mahmoud Ahmadinejad's tougher line toward the West might be gaining influence within Iran. Larijani and his replacement are both expected to go to talks with the European Union in Rome on Tuesday. Bush, at a news conference last week, said a nuclear-armed Iran would pose a "dangerous threat to world peace." "We've got a leader in Iran who has announced that he wants to destroy Israel," he said. "So I've told people that, if you're interested in avoiding World War Three, it seems like you ought to be interested in preventing them from having the knowledge necessary to make a nuclear weapon." Cheney also had some criticism for Syria, accusing it of interfering in Lebanon's attempts to elect a new president. "Through bribery and intimidation, Syria and its agents are attempting to prevent the democratic majority in Lebanon from electing a truly independent president," Cheney said. Analysts who attended the think-tank forum where Cheney spoke were struck by his tough line toward Iran, especially in light of Bush's recent comments. "The language on Iran is quite significant," said Dennis Ross, a U.S. peace mediator under former Presidents George Bush and Bill Clinton. "That's very strong words and it does have implications," referring to Cheney's warnings of serious consequences for Iran.
