FAYETTEVILLE, N.C. — They've done it in Basra, and soldiers and Marines likely will do it in Baghdad, too.

They are taking their fight from the battlefield to buildings. The challenges of fighting in cities and towns are great.

Once soldiers enter the door of a potential enemy hideout, they don't know what they'll face.

The 505th Parachute Infantry Regiment is training on room clearing. It's the type of enemy search happening in Iraq right now.

The paratroopers just returned from Afghanistan, where they found Al-Qaida members hiding among families in their homes.

The soldiers learned they couldn't just go in shooting. In a lot of instances, according to members of the unit, children were still in buildings once the soldiers cleared everyone out.

Furthermore, in urban combat, soldiers have about two seconds to assess a situation, to determine if anyone inside has a weapon or will be combative.

The soldiers don't know if a building, or even a church, is booby trapped. In a small town or large city, they don't know where a sniper could be blending in.

Even though the paratroopers of the 505th just got back from Afghanistan in January, they are on standby to deploy again within 18 hours. They could head to Iraq or anywhere else in the world. So, they know they need to remain ready for a dangerous fight.

They are well aware that urban warfare is not only more common than in battlefield wars of the past, but also more dangerous.