US Navy photo by Mass Communication Specialist 2nd Class Zachary Elmore
- US forces on Friday conducted strikes against Iran-backed groups.
- The military action comes days after a drone attack killed US troops in Jordan.
- Friday's strikes are expected to be part of a series of military actions.
The US military on Friday began strikes against Iran-backed militias in Iraq and Syria, a US defense official told Business Insider. It is expected to be part of a larger retaliatory campaign.