NEW YORK (Reuters) -- U.S. President Barack Obama's national security advisers are considering a broad range of options to curb Iran's nuclear program -- among them military strikes if diplomacy and sanctions fail, Pentagon officials say.
Defense Secretary Robert Gates, in a statement about a secret memorandum he sent to the White House in January, said he had identified "next steps in our defense planning process" that would be reviewed by decision makers in the coming weeks and months.
"There should be no confusion by our allies and adversaries that the United States is properly and energetically focused on this question and prepared to act across a broad range of contingencies in support of our interests," Gates said in the statement, issued to refute characterizations of the memo in a “New York Times” report.
Admiral Mike Mullen, chairman of the U.S. military's Joint Chiefs of Staff, said the military options available to Obama would go "a long way" to delaying Iran's nuclear progress but may not set the country back long-term. He called a military strike his "last option" right now.
The comments underscored the difficult choices facing Obama in trying to keep Iran from getting a nuclear bomb without setting off a broader conflict.
"It's very hard to predict outcomes there," Mullen told reporters after addressing a forum at Columbia University in New York.
Mullen said there was "not much decision space to work in because of both outcomes -- having a weapon and striking generate unintended consequences that are difficult to predict."
“I think Iran having a nuclear weapon would be incredibly destabilizing. I think attacking them would also create the same kind of outcome," he added.
The “Times” reported that Gates' memo was meant as a warning to the White House that the United States lacked an effective strategy to curb Iran's steady progress toward nuclear capability.
In his statement, Gates said: "The memo was not intended as a 'wake up call' or received as such by the president's national security team. Rather, it presented a number of questions and proposals intended to contribute to an orderly and timely decision-making process."
Mullen said Gates was leading policy deliberations within the administration that have had "great focus for years, not months."
"This is as complex a problem as there is in our country and we have expended extraordinary amounts of time and effort to figure that out, to try to get that right," Mullen said.
Mullen and Gates both support continuing the diplomatic and pressure track pushed by the United States at the UN Security Council, including a new round of UN sanctions aimed at persuading Iran to give up its nuclear program without resorting to military force.
A U.S. draft proposal provides for new curbs on Iranian banking, a full arms embargo, tougher measures against Iranian shipping, moves against members of Iran's Islamic Revolutionary Guard Corps and firms they control and a ban on new investments in Iran's energy sector.
"We in the Pentagon, we plan for contingencies all the time and so certainly there are (military) options which exist," Mullen said.
He said these military options "would go a long way to delaying" the nuclear program, but said Obama would have to choose how to proceed if diplomacy fails.
"That's not my call. That's going to be the president's call," Mullen said. "But from my perspective ... the last option is to strike right now."
Mullen said that his "worry about Iran achieving a nuclear weapons capability" is that other states in the region will seek nuclear arms of their own.