Fighters with Iran-backed militias in Iraq, known as the Popular Mobilization Forces, wave Iraqi flags while mourners and family members prepare to bury the body of Abu Mahdi al-Muhandis, deputy commander of Iran-backed militias who was killed in a US airstrike in Iraq on Friday, in Najaf on Wednesday. Picture: AP Photo/Anmar Khalil

Tehran, Iran – Iran struck back at the United States early on Wednesday for killing its most powerful military commander, firing a barrage of ballistic missiles at two Iraqi military bases that house American troops in what the Iranian supreme leader said was a “slap” against the US military presence in the region.

The dramatic blast of more than a dozen missiles caused no casualties, however, and US President Donald Trump said hours later that Iran “appears to be standing down”.

It was a signal that both sides were stepping away from an immediate spiral of more direct exchanges that could throw the Middle East into great turmoil.

Speaking at the White House, Trump said the US would impose new “punishing economic sanctions” on Iran to force it to stop its nuclear program and what he called its “hostilities” in the region. But he also said Washington was open to a deal with Tehran.

Iran, in turn, appeared to have calibrated its attack to avoid stoking further US retaliation, giving some early warning to its Iraqi allies to avoid casualties.