Updated

Federal and state agents have uncovered a small arsenal of home-made weapons that included a rocket launcher, 130 hand grenades and 70 improvised explosive devices (IEDs) similiar to the kind used by insurgents against American GIs in Iraq.

Agents also recovered enough live ammo to fill a U-Haul trailer, U.S. Attorney Alice Martin said Thursday. Agents earlier that day busted the caches of a group calling itself "The Free Militia."

Eric Kehn, a spokesman with the Bureau of Alcohol, Tobacco, Firearms and Explosive, said four search warrants were executed in the operation, and six arrests were made.

Those arrested include: Raymond Kirk Dillard, a.k.a. Jeff Osborne, 46 of Collinsville, Ala.; Adam Lynn Cunningham, 41, also of Collinsville; Bonnell Hughes, a.k.a. Buster Hughes, 57, of Crossville, Ala.; Michael Wayne Bobo, 30, of Trussville, Ala.; Randall Garrett Cole, 22, of Gadsden, Ala.; and James Ray McElroy, 20, of Collinsville.

All six of the suspects belonged to "The Free Militia," officials said without releasing any information about the group.

"Deadly explosives have been removed from these communities due to outstanding investigative efforts," Martin said. "All evidence developed will be presented quickly to a federal grand jury. We will also ask that those arrested be detained without bond."

At least five bomb teams were on the scene in case explosives were found during the searches.

Officials said ATF agents encountered booby traps at one of the search sites.

The weapons cache also included a machine gun, a short barreled shot-gun, two silencers, numerous other firearms, 2500 rounds of ammunition, explosive components, and commercial fireworks. Agents also found more than 120 marijuana plants, Martin said.

One of the raids took place at a trailer and another at a house not far from Collinsville School.

"Certinly, they're [militias] always fomenting talk ... they were trying to acquire, stockpile weapons for what they see as maybe some inevitable conflict. This is pretty common in militia groups — they sort of gravitate toward all these exotic military weapons," ATF Special Agent in Charge Jim Cavanaugh in Nashville, Tenn., told FOX News on Friday.

But he said it's not common to find the types of improvised rifle grenades found in Thursday's raid. It's a "very unusual seizure," he said.

Those in custody aren't being charged with any plot to use the grenades against anyone, however, but will be charged with weapons possession and stockpiling.

"These are people who operate in sort of a fringe paranoia world, they feel they need all these weapons to exist, they're somewhat fearful," Cavanaugh said.

School district officials cancelled classes for about 650 students from grades kindergarten through 12 because of the swarm of police vehicles.

"We were going to delay school but because of the possibility of explosives at the residences, we felt it was safer not to have school," DeKalb Sheriff Jimmy Harris said.

Sources told FOX News that the six suspects were involved in manufacturing homemade weapons and explosives, and that one of the suspects had tried to sell hand grenades to undercover federal agents. The group has also allegedly been involved in the sales and distribution of other types of explosive devices and weapons, but the nature of these has not yet been revealed.

"Today's arrest and search warrants have been significant due to the success of the combined efforts by ATF, as well as our state, local and federal partners," Cavanaugh said Thursday. "The communities in the area are safer, considering the fact that large quantities of live grenades and other explosive materials have been safely removed. Excellent investigative team work led us to this point in our investigation."

FOX News' Ian McCaleb and The Associated Press contributed to this report.