Earlier on Friday, military sources in Iraq said an unidentified drone had dropped explosives on a Hashd al-Shaabi military base near Amerli, east of Salahaddin province.
The attack, which was said to be two grenades half an hour apart, left to militiamen injured.
A Pentagon official said the US forces were not involved in the attack. An Iraqi official told the media anonymously that Islamic State (IS) militants were most likely behind the attack.
“We are aware of open source reports of possible aggressive actions against a Popular Mobilization Force unit in Salahaddin,” Fox News quoted Navy Commander Sean Robertson.
“US forces were not involved. We have no further information about this report,” he added.
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