Shiite Muslims demonstrate the U.S. airstrike that killed Iranian Revolutionary Guard Gen. Qassem Soleimani, in the posters, in front of Imam Abbas in Karbala, Iraq, Saturday, Jan. 4, 2020. Iran has vowed "harsh retaliation" for the U.S. airstrike near Baghdad's airport that killed Tehran's top general and the architect of its interventions across the Middle East, as tensions soared in the wake of the targeted killing. (AP Photo/Khalid Mohammed)