The U.S. carried out airstrikes against an Iranian-backed Shiite militia group in Iraq and Syria, in the Trump administration’s most forceful response to Tehran’s assertive posture in the region. The Pentagon said Sunday’s attack targeted three of the Kataib Hezbollah militia’s locations in Iraq and two in Syria, including weapons-storage and command facilities. Officials said the strikes came in response to an attack on Friday in which more than 30 rockets were fired at an Iraqi military base near Kirkuk, killing a U.S. contractor…