BAGHDAD (Reuters) – The U.S. believes the attack that killed three U.S. troops on the Jordanian-Syrian border has the “footprints” of Iran-backed Iraqi militia Kataib Hezbollah, the Pentagon said. Who is the Kataib Hezbollah? \- Founded in the aftermath of the 2003 U.S.-led invasion of Iraq, Kataib Hezbollah is one of the elite Iraqi armed factions closest to Iran. \- It is the most powerful armed faction in the Islamic Resistance in Iraq, an umbrella group of hardline Shi’ite armed groups that have claimed more than 150 attacks on U.S. forces since the Gaza war began. \- After its founding, t…