Missouri ? A military attack against Iran remains an option should the Middle East nation continue to pursue its nuclear ambitions, Defense Secretary Robert Gates said Tuesday.

“This is not about changing the regime in Iran,” Gates told a group of community leaders at a Whiteman Air Force Base lunch. “It’s about getting the regime in Iran to change its behavior, and its policies.”

Talk of a possible U.S. attack on Iran has surfaced frequently this year, prompted in some cases by hard-line statements by White House officials. President Bush has said that Iran’s continued pursuit of nuclear arms could lead to World War III.

While Gates has previously emphasized diplomacy and the use of economic sanctions, he told an audience member at the officers’ club lunch, “We have to keep all of our options open.”

At the same time, Gates added, “My own view is that another war is the last thing the Middle East needs right now.”