Thu Mar 23, 10:04 AM ET

ABU GHRAIB (AFP) - The entire adult male population of a village west of Baghdad was rounded up in a major joint US-Iraqi operation against insurgents that netted two "high value targets."

Operation Northern Lights, which involves more than 1,100 US soldiers and marines as well as Iraqi army units, is targeting bomb-making cells and weapon caches in the vast rural fields west of the capital.

"This whole area is a hotbed for insurgents, and is a major (arms) cache and transport zone," said First Lieutenant Caleb Singer, acting commander of Bravo Company, which had a leading role in the search operation.

The raid on the village of Ibrahim bin Ali began at 1 am (2300 GMT Wednesday) and is expected to last 24 hours.

US troops were airlifted in to lay a cordon around the village and then went house-to-house, rounding up men and questioning them. In one case more than 100 detainees were taken to a nearby school.

US Colonel Jeffrey Snow acknowledged that people were being temporarily inconvenienced but said it was worth it for the intelligence gathered as well as detailed sweeps of the area for weapons.

"What were doing is building a Michelin guide to area," said Snow, explaining how they were gleaning information about the family and tribal relations in the area that would help in future operations.

Snow said two "high-value targets", people directly related to anti-coalition operations -- in this case developing roadside bombs and car bombs -- had been captured.

While the men are away from the village, soldiers with bomb sniffing dogs and metal detectors will be combing the fields for weapons. In recent weeks, Bravo Company discovered a series of caches in the area containing 16 tons of munitions and explosives.

"We cant be everywhere so they keep coming back, but we are trying to wear them down," said battalion commander Lieutenant Colonel Kevin Brown.

The operation is complementary to the ongoing Baghdad-based Scales of Justice Operation implemented at the request of the Iraqi government to put more coalition troops in urban areas, according to Snow.

Operation Northern Lights, which was months in the planning, aims to choke off the supply of insurgents and munitions flowing into the capital.

Throughout the day, "tactical human teams" questioned the detainees, checking their tribal affiliations and seeing if they were familiar with the names of any of the high value targets.

Most people denied any knowledge of insurgents or their existence in the area, despite the recent discoveries of weapons caches.

"Theres a lot of intimidation out here," acknowledged one army questioner about peoples reluctance to discuss the insurgents. "The coalition hasn't really been out here."

Detainees were handcuffed with plastic ties and fed with special halal military meals and were not treated roughly, the military said. After being questioned, each man was marked with an "X" on the back of their necks.

"I know you guys get confused, its hard," one particularly understanding Iraqi told his questioner. "Its hard to tell who is a terrorist and who isnt."

Snow said the military planned to launch more positive initiatives for locals after the operation, including setting up a temporary field hospital to treat ailments for free.

"Its all a way to drive a wedge between insurgents and local nationals," said Snow.