CENTCOM Commander Admiral Brad Cooper called on the Israeli military to prepare for the third round of the military campaign against Iran.
Israeli Prime Minister Benjamin Netanyahu held an emergency meeting on security issues.
US Secretary of State Marco Rubio said the negotiations with Iran were not productive and Tehran's demands were "unacceptable, outrageous and ridiculous".
The United States ordered Iraq to close the border crossings with Iran, leaving only two checkpoints.
All Iranian missile units have been ordered to increase the level of combat readiness.