A Florida teenager has been shot dead by an armed security guard at an apartment block after he brandished a BB gun.

Stephen Brenor, 15, of Lakeland, died from gun shot injuries after he was struck by 19-year-old Shawn Plain, the guard at the Willow Glen Apartments in the city.

According to a police report, Plain was inside the laundry room at the apartment block charging his cell phone.

The scene outside the Willow Glen Apartments in Lakeland where 15-year-old Stephen Brenor was shot dead by security guard Shawn Plain, 19

He then saw a black teenager enter with what he thought was a handgun pointed at him.

The security guard then felt a stinging in his face, and believing he had been shot, pulled out his weapon and opened fire at Brenor and his friends.

The group fled the scene and tried to take cover but one of the bullets struck Brenor as he walked into the parking lot.

Plain returned to the laundry room to collect his cell phone and call 911 before discovering his victim lying on the ground.

According to Lakeland Police, the guard then apologised to Brenor when he realised his injuries.

Brenor was taken to hospital but later died as a result of a gunshot injury. He was also identified by police as a documented associate gang member.

Brenor was shot after Plain saw him brandish what he thought was a handgun and says that he acted in self defense

The gun that Brenor pointed at Plain. It has since emerged that the gun was a replica and in fact a BB gun

His black replica handgun was found on the ground next to him and police described it as a Ruger pellet gun.

Meanwhile, Plain was taken to Lakeland Regional Health Centre and treated for two pellet wounds to his face.

A Lakeland Police Department spokesman said: 'The homicide investigation is ongoing at this time as detectives continue to canvass the area and interview witnesses.'

However, Fox 13 reports that investigators are treating it as a self defense shooting and Plain is not likely to be charged.