Admiral Mike Mullen, chairman of the Joint Chiefs of Staff warned Thursday that a strike on Iran could be "very, very destabilizing" and have unintended consequences for the Middle East, adding that diplomacy was crucial.
Mullen said he believed Tehran was "on a path that has strategic intent to develop nuclear weapons and have been for some time" – a charge Iran denies.
"I think that outcome is potentially a very, very destabilizing outcome… on the other hand, when asked about striking Iran, specifically, that also has a very, very destabilizing outcome," he said.
Mullen said he worried about "unintended consequences" of either scenario, adding "that part of the world could become much more unstable, which is a dangerous global outcome."
Tehran already has been hit with three rounds of UN sanctions for refusing to comply with demands that it halt sensitive nuclear activities. The United States and its allies have said it is time for a fourth round of sanctions, but diplomats say Russia and China are resisting.
US President Barack Obama offered Iran the possibility of deeper engagement with the United States if it cooperates on removing fears about its nuclear program and on other issues. Obama had given Iran until the end of 2009 to respond to his overtures and to an offer from six major powers of economic and political incentives in exchange for a suspension of Iran's nuclear enrichment program. Iran ignored the deadline.
"One of the things that I think is so important is that we continue internationally, diplomatically, politically -- not just 'we' the United States but the international community, continue to focus on this to prevent those two outcomes," Mullen said.
Yitzhak Benhorin in Washington contributed to this report