The military has ordered increased security at recruiting centers and other facilities across the United States in the wake of the Chattanooga shootings, but many of the armed civilians said they had decided not to leave the issue of security to state, federal or military policy makers. Some said they would continue their watch until recruiters were armed or had their own guards.

“We felt that if our government wasn’t going to protect our men and women of the military at these locations, we felt it was our duty,” said Stevie D, 48, an off-duty sheriff’s deputy who stood outside an armed services recruitment center here on Tuesday with several others, including one man who carried an AR-15 style assault rifle that, he said, he had made himself.

Mr. D — who has legally changed his last name to a single letter — was armed with a .556-caliber battle rifle and a .45-caliber pistol, and had ammunition strapped to his chest.