President Bush has called Iran "the world's leading state sponsor of terror," and he urged US allies in the Gulf region to confront the danger before, in his words, "it is too late."
Speaking in the United Arab Emirates Sunday, Mr. Bush said Iran provides arms or financial support to militants in Iraq, Lebanon and the Palestinian territories.
The president said that while other countries in the region are moving toward greater openness, the Iranian government represses its people and threatens its neighbors.
Mr. Bush called on Tehran to make itself accountable to its people.
Iran's foreign ministry criticized Mr. Bush for trying to isolate the country and said Iran is improving cooperation with neighboring countries.
But Israel's Prime Minister Ehud Olmert -- during a cabinet meeting Sunday -- praised Mr. Bush's stance on Iran.
President Bush arrived in the UAE's capital, Abu Dhabi, today on the latest leg of his Middle East tour. Earlier, he ended his visit to Bahrain by having breakfast with military personnel of the US Fifth Fleet that patrols Gulf waters.
Mr. Bush used his earlier visits to Bahrain and Kuwait to praise small democratic advances in Gulf states ruled by authoritarian monarchies.
He highlighted Kuwait's decision in 2005 to give women the right to vote, and the election of a woman member of parliament in Bahrain in 2006.