The United States must "keep all options on the table" in dealing with Iran's refusal to abandon its nuclear ambitions, but the U.S. cannot act alone, Defense Secretary Robert Gates said Monday.

Gates, in remarks prepared for delivery at the Jewish Institute for National Security Affairs. called Iran "an ambitious and fanatical theocracy," and said he has yet to find "the elusive Iranian moderate."

"With a government of that nature, only a united front of nations will be able to exert enough pressure to make Iran abandon its nuclear aspirations — a source of great anxiety and instability in the region," Gates said.

Iran denies it is pursuing nuclear weapons. It says its nuclear program is strictly for civilian energy development.

"Our allies must work together on robust, far-reaching and strongly enforced economic sanctions," Gates said. "We must exert pressure in the diplomatic and political arenas as well. And, as President Bush has said, with this regime we must also keep all options on the table." The term "all options" is a veiled reference to possible military action.

Gates said Iran seems increasingly willing to act contrary to its own interests.

"We should have no illusions about the nature of this regime or its leaders — about their designs for their nuclear program, their willingness to live up to their rhetoric, their intentions for Iraq, or their ambitions in the Gulf region," he said in his prepared remarks, copies of which were made available before he spoke.

Gates also expressed a measure of doubt about the gains thus far in the administration's global war on terrorism.

"Despite many tactical successes, overall strategic success against violent extremism has been elusive," he said. "With the extent of the jihadist movement, with its breadth and numbers, even the most effective counterterrorism tactics can only reduce the number and lethality of attacks. Total elimination is infinitely more complex, part of an ideological struggle between the forces of moderation and extremism."

Gates spoke at a Jewish Institute for National Security Affairs dinner where he received the Henry M. Jackson Distinguished Service Award for leaders deemed to have honored the tradition of the late Senator from Washington state who was a leading voice in Congress on national security issues.