Fighters from Shiite Muslim-majority countries such as Iraq and Lebanon compose Iran’s main proxies, but groups in Sunni-majority Afghanistan, the Palestinian territories, Syria, and Yemen have also formed associations with Iran.

By Kali Robinson, Will Merrow, Council on Foreign Relations

The U.S. has deployed an aircraft carrier and a bomber wing days ahead of the anniversary of when America withdrew from the Iran nuclear deal.

By Jon Gambrell, Associated Press

President Donald Trump announced that the U.S. is designating Iran's Revolutionary Guard a "foreign terrorist organization," in an effort to increase pressure on the country that could have significant diplomatic implications in the Middle East.

By Matthew Lee, Associated Press