The United States is deploying jet fighters, air defenses, and an air carrier with thousands of troops to the Middle East, in a move that has heightened tensions with Iran and increased the likelihood of military action, experts say. US President Donald Trump threatened military strikes against Iran after the authorities killed thousands of people in a brutal crackdown on anti-government protests. Trump recently backed away, although he has not ruled out an attack on the Islamic Republic. Experts say the military buildup, along with planned US…