Image caption All 50 US states now offer concealed weapons permits, though the requirements differ

A gun instructor in the US state of Ohio has accidentally shot a student in the arm in a class for people seeking permits to carry a concealed firearm.

Terry Dunlap, 73, was demonstrating a .38-calibre pistol when it went off and struck Michael Piemonte, 26.

He and his wife were taking the day-long class in order to carry guns for their own safety, he told local media.

All 50 states allow residents to obtain a concealed firearm permit, though training and other requirements differ.

Last month, the state of Illinois became the last to do so, in response to a court order.

The Fairfield County, Ohio, sheriff's office listed the Saturday shooting in the town of Lancaster as accidental, the Columbus Dispatch reported.

"It took me a couple of seconds to realise that I had been shot," Mr Piemonte told CNN.

Mr Piemonte was treated in hospital and released that night.

Mr Dunlap has not spoken publicly about the incident.

Ohio residents seeking a concealed weapon permit must take an approved safety course or show "evidence of imminent danger", pass a criminal background check, and meet other requirements.