U.S. forces stationed at Ain al-Asad air base in Iraq were attacked early Tuesday prompting a U.S. military aircraft to strike back, officials said. 

Pentagon spokeswoman Sabrina Singh said Iran-backed militias used close-range ballistic missiles against U.S. and coalition forces, resulting in "several non-serious injuries and some minor damage to infrastructure." 

Reuters, citing two U.S. officials, reported that the attack resulted in eight injuries. 

A U.S. military AC-130 aircraft in the area conducted a self-defense strike against an Iranian-backed militia vehicle and personnel involved in the attack, resulting in some "hostile fatalities." 

U.S. forces have been attacked approximately 66 times since October 17, including 32 times in Iraq and 34 times in Syria. U.S. personnel have sustained approximately 62 injuries, not including Tuesday’s attack, which is still being evaluated. 

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The attacks that began on October 17 by Iraqi militia groups have reportedly been linked to the United States’ support for Israel in its retaliation against the Palestinian militant group Hamas, following its attack on Israel earlier in the month. 

Tuesday's strike was the first reported by the U.S. in Iraq in more than two years.

The U.S. has 900 troops in Syria and 2,500 in Iraq on a mission it says aims to advise and assist local forces trying to prevent a resurgence of Islamic State, which in 2014 seized large swaths of both countries before being defeated.

Reuters contributed to this report.