The top member of the Joint Chiefs of Staff  Monday described the U.S. military posture in the Persian Gulf  as "defensive and deterrent" with regard to Iran.

Gen. Martin Dempsey would not say at what point the troubled U.S. diplomatic relationship with Iran over that country's nuclear program would or could escalate.

"That's not my call to make," Dempsey said during a Memorial Day appearance on "Good Morning America." "My job is to provide options on behalf of the joint chiefs and the combatant commanders to the commander in chief, who will then determine when the  current track, which as you know emphasizes political, diplomatic and economic sanctions  … is exhausted."

Dempsey's comments came the day after Defense Secretary Leon Panetta struck a resolute tone against Iran during an interview on "This Week" with ABC's Jake Tapper.

"The fundamental premise is that neither the United States or the international community is going to allow Iran to develop a nuclear weapon. We will do everything we can to prevent them from developing a weapon," said Panetta. "International community's been unified. We've put very tough sanctions on them as a result of that, and we are …  prepared for any contingency in that part of the world. But our hope is that these matters can be resolved diplomatically. "

Tapper pointed to recent comments made by the U.S. ambassador to Israel that the U.S.  is "ready from a military perspective to carry out a strike on Iran."

Panetta said, "One of the things that we do at the Defense Department, Jake, is plan. And we have plans to be able to implement any contingency we have to in order to defend ourselves."

Dempsey echoed that language about defense and emphasized that the U.S. is already engaged in other operations in that part of the world.

"I've got - we've got - forces postured in the Gulf for any number of reasons. Some in support of Afghanistan. Some that are still in the process of flowing out after the end of a long war in Iraq, and those forces can be turned, but there are no …  I would describe our current stance in the Gulf as defensive and deterrent in nature," he said.

Dempsey also discussed the coming drawdown of U.S. troops in Afghanistan before the planned cease of combat operations for NATO forces at the end of 2014, and also reflected on the sacrifices of the fallen on Memorial Day.

Watch Dempsey on "GMA ":