In the week since Iraq launched an operation to retake Mosul from the Islamic State group, its forces have pushed toward the city from the north, east and south, battling the militants in a belt of mostly uninhabited towns and villages.

In the heavily mined approaches to the city, they met with fierce resistance as IS unleashed suicide truck bombs, rockets and mortars. In other areas, the militants retreated, and in at least one village civilians rose up and overthrew them before the troops arrived.

IS meanwhile launched a massive assault on the city of Kirkuk, some 170 kilometers (100 miles) away, killing at least 80 people in two days of clashes in an apparent attempt to divert Iraqi forces.

Here is a look at the main developments during the first week of the offensive:

TERRITORIAL GAINS

Iraqi special forces captured Bartella, a historically Christian town some 15 kilometers (9 miles) east of Mosul, and celebrated victory by raising the Iraqi flag over its church and ringing the church bell.

The Iraqi army's 9th Division pushed into the nearby town of Hamdaniyah and said it captured the main government compound. To the north, Kurdish forces known as the peshmerga have driven IS out of several villages and, along with Iraqi special forces, have encircled the town of Bashiqa.

Progress has been slower to the south of Mosul, where troops have only advanced to around 50 kilometers (30 miles) from the city. They were hampered over the weekend after IS torched a nearby sulfur plant, sending a cloud of toxic fumes into the air that mingled with smoke from oil wells the militants had lit on fire.

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U.S. ROLE

The U.S.-led coalition is providing airstrikes and ground support, with more than 100 American soldiers embedded with Iraqi units and hundreds more in staging bases near the front lines. An American soldier was killed by a roadside bomb near Bashiqa, marking the first U.S. casualty of the operation.

The peshmerga said Sunday that 25 of its fighters have been killed since the operation began. The Iraqi military has not released any casualty figures. Iraqi and Kurdish forces have asked for more coalition airstrikes, and the Kurds have requested more armored vehicles and roadside bomb detectors. They say most of the fallen peshmerga troops were traveling in unarmored vehicles.

Two Iraqi television reporters have also been killed, one while covering the fighting south of Mosul and the other while covering clashes in Kirkuk

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HUMANITARIAN FALLOUT

The U.N. and aid organizations say some 5,000 civilians have been displaced since the operation began, a tiny fraction of the 1 million people remaining inside Mosul.

Aid groups fear that a mass exodus from the city could overwhelm camps set up around its outskirts, and the Iraqi government has called on Mosul residents to remain in their homes. Aid groups also fear that IS, which has been killing alleged informants in Mosul in recent weeks, may use civilians as human shields.

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TENSIONS WITH TURKEY

The launch of the Mosul operation has aggravated tensions with neighboring Turkey over the presence of some 500 Turkish troops at a base near Bashiqa, where they are training Kurdish and Sunni fighters who are taking part in the offensive.

Baghdad says the troops are there without its permission and has ordered them to leave. Ankara has refused, insisting that it play a role in the Mosul operation. Turkey is closely allied with the Sunni former governor of Ninevah province, where Mosul is the capital, and Kurdish leader Masoud Barzani, both of whom have pressed for greater autonomy from Iraq's Shiite-dominated central government.

U.S. Defense Secretary Ash Carter visited the region in part to try to ease tensions between the two U.S. allies, but did not appear to make much progress, as both sides stood by their demands.

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WHERE WE GO FROM HERE

Iraqi Prime Minister Haider al-Abadi insists the operation is progressing ahead of schedule. But the fight to retake Mosul, Iraq's second-largest city, is expected to take weeks, if not months.

Iraq's army and police are still rebuilding from their humiliating defeat in the summer of 2014, when IS seized Mosul and much of northern and central Iraq in a matter of days. They have struggled in the past to make progress on more than one front simultaneously, and they have only advanced a few kilometers (miles).

As they get closer to the city and take the fight to more populated areas, they will have to rely less on coalition airstrikes and heavy shelling. The militants will have a dense urban environment in which to hide, and they've had two years to prepare.

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Krauss reported from Baghdad.

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