Police officials in the area said Islamic State militants were involved in the attack and the mortars were fired from a nearby mountainous area were militants are still active.
"Daesh (Islamic State) fighters are hiding in (the) Makhoul mountains area and use it as a launchpad for their attacks," said Shirqat police colonel Khalil Sahan.
Islamic State has recently mounted a series of hit-and-run attacks aimed at undermining the government.Iraq declared victory over the group, which once held large swathes of the country, in December 2017. But after they were defeated and driven out of areas they controlled for years, the militants have adapted their tactics to insurgent-style attacks.