Iran’s top general, Qassem Suleimani, was killed by a US rocket strike last week.
The strike near Baghdad’s International airport killed 10 people.
The late head of Iran's Islamic Revolutionary Guard Corps' Quds Force has spent decades building up Tehran's army of proxy militia and allies from Beirut to Sanaa.
Iran promised severe revenge, and it came in the form of 22 rockets fired at US troop locations on Iraqi bases.
The latest escalation comes on the back of 18 months of slowly rising tensions.
In this week's Beyond the Headlines, Foreign Editor James Haines-Young talks to The National's Editor in Chief, Mina Al-Oraibi and experts about where this rocky relationship is headed.