The US has contingency plans to deal with Iran's nuclear programmes, the top US military commander told CNN on Sunday, in addition to diplomacy and sanctions.
While General David Petraeus, head of US Central Command, did not elaborate on the plans, he said the military has considered the impact of any action taken there.
"It would be almost literally irresponsible if Centcom were not to have been thinking about the various 'what ifs' and to make plans for a whole variety of different contingencies," Petraeus told CNN.
However, he declined to comment when asked about rumours that Israel could attack Iran's facilities. Israel has repeatedly said that Iran's nuclear programme was a major threat to it.
Petraeus also said there was still time for world powers to engage Iran in diplomacy, adding that there was no deadline on the enactment of any US contingency plans.
"There's a period of time, certainly, before all this might come to a head, if you will," he said.
Diplomats from six countries are scheduled to meet mid-January to discuss the "next steps" in dealing with Iran. The countries involved are the UN Security Council's five permanent members - the US, Russia, China, France and Britain - plus Germany.
The council has in the past three years imposed a series of sanctions to curb Iran's needs for nuclear technology and resources. But those measures have failed to slow down Iran's expansion of its uranium enrichment programme, which Western governments say is a cover for manufacturing nuclear weapons.
US Secretary of State Hillary Rodham Clinton said last week that her government had not closed the door on negotiations with Iran in the nuclear dispute.