An Iranian official, Gen. Amir Ali Hajizadeh, a top general of Iran's Revolutionary Guard, said that Iran will target US bases in the region if Israel launches any attack against Iran. Gen. Hajizadeh said that no attack by Israel could be launched without the support of it's greatest ally, the United States, and that makes any US bases legitimate targets. In addition to numerous bases in Afghanistan, the US Fifth Fleet is based in Bahrain.
In addition to threatening the US bases in the region, Iran has also threatened to close the Strait of Hormuz, a waterway that carries a fifth of the world's oil.
Israeli Prime Minister Benjamin Netanyahu says that diplomacy and international sanctions have failed, and the United States should declare "red lines" that would trigger an immediate attack of Iran by US forces. President Obama has rejected these calls and has encouraged more time for diplomacy and sanctions to work.