The massive U.S. military buildup in the Middle East, including warships, fighter jets and refueling aircraft, lays the foundation for a potentially sustained campaign against Iran ¡ª should U.S. President Donald Trump give the order.

Trump ¡ª who ordered strikes on Iran last year ¡ª has repeatedly threatened Tehran with further military action if ongoing talks do not reach a replacement for the nuclear deal the U.S. president tore up in 2018, during his first term in office.

The presence of "so much firepower ... in the region creates a momentum of its own," said Susan Ziadeh, a senior advisor at the Center for Strategic and International Studies.