President Biden has vowed to respond after three U.S. soldiers were killed in a drone strike on an American base near the Jordan-Syria border. The attack was claimed by the Iran-backed group Islamic Resistance in Iraq. There are around 40 militant groups backed by Iran in the region, including the Houthis in Yemen and Hezbollah in Lebanon. The Iran-backed militant groups aim to support the survival of the Syrian regime and pay close attention to U.S. activities in the region. The Islamic Resistance in Iraq is believed to answer to Iran’s Supreme Leader and relies on Iran for support and weapons.