The US has launched a drone strike against a top commander of an Iran-backed militia in Baghdad, according to an official in Washington.
Iraqi security sources say the attack on a vehicle killed at least three people, including the leader of Kataib Hezbollah.
The US blames the Iranian-backed group for launching an attack that killed three American troops at a base in Jordan.
The retaliatory strike by the US on Wednesday was in Baghdad’s eastern Mashtal neighbourhood.
One of those killed was a commander of the Kataeb Hezbollah group in charge of military affairs in Syria, a member of the pro-Iran Iraqi group told AFP.
There was the wreckage of a car with witnesses reporting a series of deafening bangs.
The latest strike was nearly a week after the United States struck 85 targets at seven different sites in Iraq and neighbouring Syria of Iranian and pro-Iranian forces.
US and allied troops have been attacked more than 165 times in the Middle East since mid-October in a campaign by Iran-backed armed groups angered by US support for Israel in the war in Gaza.
The United States has branded Kataeb Hezbollah a terrorist group.
Officials in Washington have indicated they believed the group was behind the Jordan attack.
A security source told AFP that the drone in Wednesday’s attack had fired three rockets at a 4X4 car.
Later in the evening the wreckage of a vehicle was removed from the area.
The United States and Iraq have opened talks on the future of the US-led troop presence in January, following a request by the Iraqi prime minister for a timetable for their withdrawal.
The United States has around 900 troops in Syria and 2,500 in Iraq as part of an international coalition against the Islamic State group.