FBI investigating explosion outside NAACP office

COLORADO SPRINGS -- The FBI is investigating an explosion outside a local NAACP chapter in Colorado.

The makeshift bomb, or improvised explosive device, detonated late Tuesday morning but failed to ignite a gasoline can placed alongside it. No one was injured but the incident left some in Colorado Springs shaken.

"All of a sudden I heard this big boom," one witness told CNN affiliate KDVR. "There was smoke everywhere the building on the side was burnt."

The witness continued: "Whoever did it took off right away though. That's all I heard and it was scary."

The FBI has not said if the NAACP was specifically targeted. But some pointed out that the other tenant in the building, Mr. G's Hair Design Studios, likely was not.

"Who would want to bomb a beauty salon?" one member of the local NAACP chapter told CNN affiliate KCNC.

Henry D. Allen Jr., the branch's president, also raised the specter of a targeted attack, telling KCNC, "Apparently, we're doing something correct. Apparently, we have gotten someone's attention that we are working toward civil rights for all. That is making some people uncomfortable."

The NAACP is the nation's oldest civil rights organization. The group's national office says it is looking forward to a "thorough investigation" into the explosion by national and local authorities.

The FBI has asked that anyone with information call its Denver tip line at (303) 435-7787.