U.S. and Iraqi soldiers have completed an air-and-ground assault in a region where military officials say roadside bombs were manufactured in northern Iraq.

The raids focused on an area called the Rashaad Valley, just outside of Kirkuk, officials said.

Soldiers from the U.S. 2nd Battalion, 35th Infantry, 25th Infantry Division undertook the mission with the Iraqi army’s 2nd Battalion, 3rd Brigade, 4th Army Division.

The valley stretches from the southern end of Kirkuk and at one point runs between the two major roads leading to the city. Military officials believe that most of the bombs planted on these roads are put there by insurgents who live in villages in the valley.

“There’s a lot of enemy activity in the form of [bombs] and other criminal cells that operate in the area,” said Capt. Jonathan Graebener, commander of Company A, 2nd Battalion, 35th Infantry Regiment.

“Additionally, this particular location doesn’t receive a lot of attention from the government in terms of infrastructure repair and other basic needs because of the poor security situation.

“The goal was to go into these villages to disrupt, detain and capture [bomb] cells and networks, and to make an assessment of the eight villages for future civil military operations.”

A public affairs official with 25th ID’s 3rd Brigade said the roadside bomb threat is the biggest security challenge for U.S. troops in the region. One battalion within the division, he said, has lost seven soldiers to roadside bombs since the deployment began last year.

While specific numbers of arrests and seized weapons were undisclosed, officials said several members of the bomb-making cells were captured, along with both finished and unfinished roadside bombs.