US Defense Secretary Robert Gates believes that Iran's nuclear program is the greatest current threat to global security. "Iran is the one that concerns me the most because there don't seem to be good options [or a scenario] where one can have any optimism that good options will be found," Gates told the Economic Club of Chicago. He bewailed the international community's inability to affect Iran's apparent determination to seek a nuclear weapon. "All of the outcomes are negative," he continued. "If they achieve one, the possibility of a nuclear arms race in the Middle East is very, very real. "If something is done to prevent them from getting one, the consequences of that are completely unpredictable and frankly, very bad." Gates lamented that he hadn't been able to persuade other nations, particularly Russia, that the Iranian nuclear issue did not simply just threaten the United States, AFP reported. "Iran's going to have the capability to deliver nuclear weapons to the people in their region a lot sooner than they're going to have the capability to deliver them to us," he added.