“President [Donald] Trump ordered the assassination of a national hero for Iran and a hero for the region,” said Iran’s Foreign Minister Mohammad Javad Zarif of the killing of powerful Iranian Gen. Qasem Soleimani in a US drone strike back in January. The attack on Soleimani’s convoy outside Baghdad’s International Airport also left several others dead, including pro-Iran Shiite commander Abu Mahdi al-Muhandis. 

Addressing a virtual meeting of the US-based think tank Council on Foreign Relations, Zarif called the killing “a great mistake” by the United States, adding that “the book” on Iran’s retaliatory measures “is not closed.” However, he noted, “I’m not in the business of making threats,” suggesting that any decisions about retaliation lie with Iran’s Supreme Leader Ayatollah Ali Khamenei, who is constitutionally the commander-in-chief and holds the ultimate authority over all sensitive foreign policy matters.

Five days after Soleimani's killing, Iran targeted Al-Asad Airbase housing US troops in Iraq with a barrage of missiles, leaving behind a trail of destruction but no confirmed deaths. Those were not all the missiles Iran fired during that night: In a state of high alert anticipating US retaliation, Iranian forces mistakenly downed a passenger plane outside the capital Tehran, killing all 176 people on board, most of them Iranian nationals.

To the Iranian supreme leader, the attack on the American base was just a “slap in the face.” He stressed that revenge will not be complete until all US troops are withdrawn from the region. His warning prompted speculation that the Islamic Republic will take aim at American troops stationed in its vicinity through a web of regional proxies it has been nurturing and arming during the past two decades.