Lawmakers in the US state of Tennessee on Tuesday passed a bill allowing teachers, principals and other school personnel to carry concealed handguns, a year after a deadly shooting at an elementary school in the state.

The measure passed the state's House of Representatives after being approved by its Senate earlier in April, sending it to Governor Bill Lee, who previously said he is "open" to the gun-carrying idea and has reportedly never vetoed a bill.

The legislation sets out various requirements for school employees to be permitted to carry handguns, including completing 40 hours of "basic training in school policing" in addition to a further 40 hours of training per year.

The measure was passed a little more than a year after an assailant opened fire at an elementary school in Nashville, killing three children and three staff before being killed by police.

Tennessee's Republican-led legislature expelled two Democratic lawmakers who led gun control protests at the state capitol in the wake of the shooting.

School shootings are strikingly common in the United States, as are calls for tighter gun control measures in their aftermath.

But federal action on the issue has been limited, leaving states and local councils to enact their own rules on firearms, which can differ widely between different jurisdictions.