BAGHDAD — Retaliatory strikes near the Iraqi-Syrian border Dec. 29 on Iran-linked armed groups, after an attack on a base near Kirkuk that killed a US contractor two days prior, may mark a significant escalation between the major foreign powers vying for influence in the country.

The target, Kataib Hezbollah (KH), is considered a terrorist organization by the United States. Part of it has been incorporated into official Iraqi government forces within the Popular Mobilization Units (PMU).

A statement by US Assistant to the Secretary of Defense Jonathan Hoffman released immediately after the attack on the evening of Dec. 29 said the United States had “conducted precision defense strikes against five KH facilities in Iraq and Syria that will degrade KH’s ability to conduct future attacks” against Operation Inherent Resolve (OIR) forces, the name given by the United States to its military intervention against the Islamic State (IS) in Iraq and Syria.

A KH regiment commander and aide to the 45th brigade commander, Abu Ali al-Khazali, was one of dozens killed in the attack.