isis mosul
An Islamic State group militant waves a flag as the group celebrates in the city of Mosul, Iraq, June 23, 2014. Reuters/Stringer

ISTANBUL -- The U.S. and the Iraqi army, along with Kurdish military forces, are planning a major assault on the Islamic State group in Mosul, but the group is preparing to move its operations to a different town closer to the oil-rich city of Kirkuk, Sunni tribal fighters in Iraq told International Business Times. The Sunni militant group is focusing its efforts on creating a new base in Iraq in Hawija, a Sunni-majority town southwest of Kirkuk where militants held a parade over the weekend displaying Kurdish soldiers as hostages in cages.

International media originally reported that the Kurdish soldiers had been paraded through the streets of Kirkuk, raising the possibility that the terrorist group was taking over a major city that the Kurdish regional government relies on for oil funds and economic stability. But the parade by the group, also known as ISIS or ISIL, was actually held in the town of Hawija, about 35 miles (55 km) from Kirkuk and its oil.

Hawija is a Sunni-dominated town off a major highway that leads from Mosul to Baghdad, and it was first infiltrated by ISIS in June. Since then, the group has taken over several small villages surrounding the town, but now it has gained enough ground and support from local people -- most of whom belong to the same branch of Islam as ISIS -- to develop its new headquarters in Iraq.

For the past nine months ISIS headquarters in Iraq has been Mosul, Iraq's second-largest city, which it took over last summer. Mosul has offered the Sunni militant group a strategic advantage: It is close enough to the Syrian border that the group has been able to access trade routes to smuggle weapons and fighters.

The U.S.-led coalition has bombarded the city and its surrounding areas for months, targeting ISIS convoys and weapons-storage centers. The U.S. said last week that it was helping the Iraqi and Kurdish militaries prepare to launch a large-scale attack to take back Mosul. The U.S. Central Command said last week that U.S. forces were training about 20,000 soldiers to take back the ISIS headquarters in Iraq, which currently houses about 2,000 militants.

But as the Iraqi and Kurdish militaries prepare to take back Mosul, ISIS is slowly transitioning its soldiers and weapons south to the Hawija area. The group's position in Hawija gives it access to Anbar province to the west of the town and where ISIS has been advancing over the past two weeks. Sunni tribal fighters on the ground there told IBTimes that the group now controls about 80 percent of the province.

The new Hawija headquarters would give ISIS access to a road that leads to the Baiji refinery, which the group lost to the Iraqi military in November. The oil fields surrounding Kirkuk, however, are a long distance from Hawija and are still under control of Kurdish forces.