The initial breakthrough with Turkey came as three suicide bombers attacked a government center in Diyala Province, northeast of Baghdad, killing 60 people and wounding more than 120, officials said. Many of the victims were people who had sought refuge in the district, Qara Taba, after fleeing violence elsewhere in the country, officials said. They had gathered at the government center to collect subsidies for displaced people.

Earlier in the day, the police chief of Anbar Province in western Iraq was killed when two bombs planted along a rural road were detonated as his convoy drove by, officials said. Anbar officials said the death of the chief, Maj. Gen. Ahmed Saddag, was a setback to the efforts of the Iraqi security forces to wrest full control of the province from the jihadist insurgency called the Islamic State.

Iraqi forces have been struggling to push the Islamic State fighters from territory they captured this year. The group, also known as ISIS or ISIL, first made inroads in Iraq at the beginning of the year when it swept from Syria into Anbar Province and quickly seized control of territory throughout the Euphrates River valley, from the Syrian border to the rural western suburbs of the Baghdad area.

In June, another wave of fighters poured across the Syrian border into northern Iraq, quickly overwhelming Iraqi security forces in the city of Mosul. They have since expanded their control across areas of northern and central Iraq.