Americans think Iran is the country that poses the greatest immediate danger to the United States today, taking over the number one spot from North Korea. A FOX News poll released Thursday shows the public is concerned about Iran attacking the United States with nuclear weapons, and even more concerned about Iran supplying nukes to terrorists.

If Iran were to obtain nuclear weapons, an overwhelming 91 percent of Americans say they are concerned it would sell them to terrorists, including 68 percent that say they are very concerned.

In addition, eight in 10 Americans are concerned Iran would use nukes to attack a neighboring country (54 percent very concerned), and 73 percent are concerned it would attack the United States (47 percent very concerned).

Iran tops the list when respondents are asked to say which country — without being read a list — poses the greatest immediate danger to the United States. Today a 28 percent plurality says Iran, up from 18 percent a year ago. North Korea, which was first on last year’s list, comes in second this time around at 17 percent, down from 26 percent (January 2005). Iraq (16 percent) and China (14 percent) are other common mentions.

Opinion Dynamics Corporation conducted the national telephone poll of 900 registered voters for FOX News on January 24-25.

Over half of Americans think Iran is either an immediate (16 percent) or near-term threat (40 percent) to the United States, while about a third (34 percent) think it is more likely to be a long-term threat. Few think Iran does not pose a threat at all (7 percent).

Most of the public believes Iran wants to use uranium enrichment for military purposes (82 percent) rather than for the peaceful purposes it claims (8 percent). Furthermore, 68 percent believe Iran currently has a nuclear weapons program, up from 60 percent a year ago (January 2005).

"These broad evaluations of Iran as a present and growing threat highlight the truly perilous situation most Americans see outside our boarders," says Chris Anderson, Opinion Dynamics senior researcher. "We haven’t even finished one war and many already see the potential need for another."

By a wide margin, Americans think Iran is more of a threat to the world than Iraq was before the United States took military action there. Nearly half (47 percent) think Iran is more of a threat than Iraq was, while 25 percent think less of a threat and 19 percent the same.

If diplomacy fails, 59 percent support using "whatever military force is necessary," to keep Iran from getting nuclear weapons; however, when presented with specific military options support drops. Some 51 percent support using only air strikes, and 46 percent support using air strikes and ground troops.

A 54 percent majority is confident in the ability of the Bush administration to handle the situation with Iran, while slightly fewer (46 percent) are confident in the ability of the United Nations to handle Iran.

• PDF: Click here for full poll results.