A school system in deep southwestern Virginia has filed a lawsuit challenging the state’s decision to bar the system’s employees from carrying firearms.

Lee County Public Schools is asking a circuit court judge to order the Virginia Department of Criminal Justice Services to allow the system’s superintendent to become a special conservator of the peace, a designation county officials believe would permit him to carry a gun on school property.

“We believe that we have legal grounds to provide this as an option to our staff and to provide an additional layer of security for our students,” Superintendent Brian Austin said.

The lawsuit names Shannon Dion, director of the Virginia Department of Criminal Justice Services, and Brian Moran, state secretary of public safety and homeland security, as defendants. Dion did not respond to a message seeking comment. Moran declined to comment on pending litigation.

A spokesman for Attorney General Mark R. Herring (D) reiterated Herring’s view that the county’s plan is unlawful.

“Attorney General Herring has explained in an official opinion that Virginia state law does not allow for armed teachers, and for good reason,” spokesman Michael Kelly said. “We will work with our client agency to respond to the suit in court.”

The plan to form a volunteer cadre of armed school employees, all of whom would undergo psychological evaluation, background screenings and firearm training, was approved by Lee County’s school board in July.

Schools officials said they spent more than a year developing the plan but that events — including the February shooting at Marjory Stoneman Douglas High School in Parkland, Fla., that resulted in 17 deaths pushed them to implement it.

Austin submitted an application with the Department of Criminal Justice Services last year to register as a special conservator of the peace, a classification the district believed would enable it to outfit teachers and other school employees with guns.

However, the Department of Criminal Justice Services rejected Austin’s application in September and, on Friday, sustained the decision after Austin appealed.

The state agency relied on an advisory opinion from Herring that differentiated between “conservators of the peace,” such as judges and other state or federal employees, and “special conservators of the peace,” who are appointed by a circuit court.

Conservators of the peace, Herring wrote, are allowed to carry firearms in schools but special conservators of the peace are not.

“Virginia law expressly limits who may possess firearms on school grounds for safety purposes, and the General Assembly declined to enact bills presented every year from 2013 through 2017 to extend this authority to school teachers and administrators,” he wrote.

The lawsuit pits Herring’s interpretation of state law against that of former attorney general Ken Cuccinelli II, who is representing Austin. He said the state is “attempting to stand in the way” of a school system making a policy choice.

“The Lee County School Board has the legal right to decide to utilize vetted, trained, armed employees to protect the children in their care,” Cuccinelli said.

Austin fulfilled the requirements to become a special conservator of the peace, which meant the state “had no authority” to reject his application, the lawsuit contends.

The county, which borders Kentucky and Tennessee, has five school resource officers — law enforcement officials who are assigned to its 11 schools. Officials say the cash-strapped district, which is beset with $110 million in recommended renovations and construction, cannot afford to hire more.

The salaries of three school resource officers are covered by grants that have no guarantee of being renewed, according to the school system.

More than a dozen Lee County school employees are seeking to become special conservators of the peace, some of whom have already gone through training. The county has purchased 9mm handguns that are stored in the Lee County Sheriff’s Office; they were partially paid for with school system money, Austin said.

He declined to say how many guns were purchased or how much they cost.

Laura Vozzella in Richmond contributed to this report.