BAGHDAD, Dec. 5 (Xinhua) -- A total of two mortar rounds hit on Thursday an air base that houses U.S. troops in Iraq's central province of Salahudin, a provincial police source said.
The incident took place in the evening when the two mortar rounds landed in Balad air base, some 80 km north of the Iraqi capital Baghdad, the source told Xinhua on condition of anonymity.
Initial reports said that the attack left no human casualty but caused slight damage to some buildings, the source added.
Balad air base is the largest military air base in Iraq, also known by the U.S. forces as Logistics Support Activity Anaconda.
Two days ago, the media office affiliated with the Iraqi Joint Operations Command said in a statement that five rockets struck the Ain al-Asad air base, where hundreds of U.S. troops are stationed, but caused no casualties.
Over 5,000 U.S. troops have been deployed in Iraq to support the Iraqi forces in the battles against Islamic State (IS) militants, mainly providing training and advising to the Iraqi forces.
The troops are part of the U.S.-led international coalition that has been conducting air raids against IS targets in both Iraq and Syria.