The two drivers involved in an alleged road-rage incident early Monday morning both say they believed the other was a threat.

Leonard Young is accused of firing at least 15 rounds at another vehicle on a frontage road off Interstate 635 shortly after 1 a.m.

Marcus Scott said he called 911 because Young was driving so erratically that he thought he was drunk. Mesquite police said Scott called shortly after 1 a.m. while heading west on Interstate 30 near Interstate 635 and then tailed the vehicle south on Interstate 635.

Sgt. Brian Parrish said the other driver stopped his vehicle in a lane of traffic on the frontage road at Town East Boulevard, exited his car and fired at the caller.

"Anybody that would spray 15 bullets across 635 the way that man did, that ain't right," Scott said. "He had no care for anybody but himself, and he knew he wasn't a threat. He was trying to shoot me; that's all it was to it. It was scary; I won't lie."

Scott was grazed in the head by one bullet. Police said his injuries did not appear to be life-threatening, police said.

Young, a commissioned security guard who has a conceal-carry permit, said he fired in fear of his life.

Young said he felt his life was in danger because Scott had his window down and Young thought he leaned over to perhaps grab a weapon. He said he felt like Scott tried to run him over.

"Either way, you know, I fired a round to get him to get away from me, because I'm like, you know, I think he's trying to kill me when he's doing that, when he's driving his car towards me," Young said.

Young, who said he had been shot before, said he thought he fired three times but because he was scared and shaken up "apparently I shot the whole magazine."

Police said Young called police after the shooting and drove to the station to speak with officers. Young, who is charged with aggravated assault with a deadly weapon, is free on bond.

NBC 5's Randy McIlwain contributed to this report.