Iraqi security forces clashed with ISIS north of Baghdad on Saturday, leaving at least two security personnel and five insurgents dead. The confrontation occurred when a joint force of army troops and state-sponsored tribal fighters raided an ISIS hideout in the Tarmiyah plains, the military said. "We had learnt that ISIS was holding a meeting there to plan for attacks on the capital Baghdad," Ahmad Salim, head of the Baghdad Operations Command, said. The military said two members of the tribal pro-government forces were killed, along with five ISIS fighters. Prime Minister Mustafa Al Kadhimi met top military commanders as troops combed the fields around Tarmiyah, 35 kilometres north of Baghdad. While the operation was underway, an unknown armed group fired three rockets at the nearby Balad airbase. Iraqi F-16s at the base were providing air cover for the army in the Tarmiyah operation, at the time of the attack, according to a source spoken to by AFP. There was no immediate claim of responsibility and it was not clear whether the rocket attack was linked to the anti-IS operations. But the news agency Sabreeen, which has been linked by analysts to Iran-backed militias, said that a Shiite militia group had carried out the rocket attack, in an attempt to target American contractors working as ground crew at the base. Balad is around 60 kilometres north of Tarmiyah. One rocket hit a runway, without disrupting the take-off and landing of aircraft, while a third hit nearby woodlands, the source said. The Tarmiyah operation comes nearly a month to the day since twin suicide bombers killed more than 30 people in Baghdad's Tayaran Square, the bloodiest such attack in the capital in three years. Security sources said the two bombers had infiltrated the city from the north. A few days later, nearly a dozen fighters from Iraq's Hashed Al Shaabi, a powerful network of state-sponsored groups, were killed in an ISIS ambush – also north of the capital. Since then, security forces have ramped up their efforts to hunt ISIS sleeper cells there, with Mr Al Kadhimi announcing the killing of Abu Yasser Al Issawi, identified as the top ISIS figure in Iraq, on January 28. In early February, security forces killed another ISIS leader, who they believed helped transport the twin bombers into Baghdad. Iraq declared ISIS territorially defeated in late 2017 after a three-year fight aided by US-led coalition air strikes and military advisers. ISIS attacks in urban areas have dramatically dropped since then, but Iraqi troops have continued to battle sleeper cells in the country's mountainous and desert areas.