US presidential candidate Mitt Romney took a hard line on Iran in a speech in Jerusalem on Sunday. The Republican White House hopeful said that when Iran's leaders deny the Holocaust or speak of wiping Israel off the map, only the naive or worse will dismiss it as rhetoric. Romney said that a nuclear Iran must be prevented. He said Iran is closer to develpoing a nuclear capability, and preventing that outcome nust by the highest national security priority, with no options excluded. In his speech, Romney also declared Jerusalem the capital of Israel. Romney later dined with Prime Minister Binyamin Netanyahu and his wife Sara. Earlier in the day, he had meetings with Israeli leaders, including Prime Minister Binyamin Netanyahu, President Shimon Peres and Kadima party leader Shaul Mofaz. A meeting with Labor Party leader Shelly Yechimovich was cancelled. Romney is due to attend a campaign fund-raiser in Jerusalem on Monday. From Israel, the former Massachusetts governor heads to Poland on a trip abroad aimed at boosting his foreign policy credentials.