Republican presidential candidate Donald Trump speaks during a campaign stop in Windham, N.H. (Jim Cole/AP)

Officials in Virginia’s largest jurisdiction want to close public schools during the Super Tuesday presidential primaries, saying they fear that supporters of Republican front-runner Donald Trump could cause mayhem at the polls.

The concerns stem mainly from a state Republican Party decision — which Trump opposes — to require voters to affirm that they are Republicans before casting a ballot in the March 1 Republican presidential primary.

“If you say: ‘I don’t want to do it,’ I have to say: ‘You don’t get a ballot,’ ” Fairfax County Electoral Board Secretary Katherine K. Hanley told the county Board of Supervisors on Tuesday before it voted to ask school officials to keep students home.

“That’s what this provision is,” said Hanley, a Democrat who chaired the county Board of Supervisors from 1995 to 2003 and later served in the Cabinet of Gov. Timothy M. Kaine (D). “That’s about as contentious as anything we can possibly be doing in a polling place on Election Day.”

Virginia voters do not register by party, and some Republican leaders in the state say the pledge will keep Democrats from casting ballots. Others, including Trump, argue that it could dissuade voters who want to support a Republican candidate but are frustrated with the party establishment.

A total of 167 schools in Fairfax will be used as polling stations for the primaries, with up to 250,000 voters expected. Although voting generally takes place in gyms and cafeterias while students are elsewhere, Hanley said she believes the risk of arguments or fights over the pledge is significant enough to justify canceling classes for the county’s more than 180,000 students.

Corey A. Stewart, chairman of Trump’s campaign in Virginia, called such concerns “preposterous,” saying there have been no threats of violence over the issue.

“This is just an attempt by Democrats and probably some establishment Republicans to malign and disparage Trump supporters and also to characterize conservative speech as hate speech,” said Stewart, a Republican who is chairman of the Prince William Board of County Supervisors.

Fairfax school officials decided in October to open schools two hours late on March 1, to accommodate what is expected to be an unusually high number of primary voters in an election that has 13 Republican and three Democratic candidates. In past years, schools have been open during primaries but closed for the general election in November, when turnout is higher.

Fairfax County Public Schools Superintendent Karen Garza said the request to close the schools for the primary “came as a complete surprise.” She said she would consult with county officials, but for now, she did not believe such a step was necessary.

“For many years, schools have been open and serving as polling locations without incident,” Garza said in a statement. “We work closely with election officials, our security team and law enforcement to ensure the safety of all.”

A Fairfax police spokeswoman said law enforcement authorities so far do not believe that the primary poses any unusual security challenges.

In neighboring Loudoun County, General Registrar Judy Brown said well-publicized incidents of scuffling and name calling at Trump rallies across the country have sparked fear among some primary-day volunteers.

“We have had people saying they would prefer not to work the election,” Brown said. She said she is talking to county officials about whether to implement extra security precautions but nothing has been decided.

Election officials are expecting about 10 percent more voters than in 2008, the last time both parties held a presidential primary. Some officials said their concerns were focused on crowds, rather than on Trump or the pledge.

Michele White, general registrar in Prince William County, said she’s worried about a lack of space inside the 76 county schools that are used as polling stations. Prince William School Board Chairman Ryan Sawyers said he would support closing schools for the day to “allow for more voter access and allow for more teachers to vote.”

Fairfax County Supervisor John Cook (R-Braddock) raised the point that voters don’t have to go through the usual school security procedures when entering. “We are putting out a sign to every predator and anyone who wants to get in and cause mischief with our children if we have school open during this primary,” Cook said.

Fairfax County supervisors voted 9 to 1 to ask the school system to cancel classes.

The lone no vote was Kathy Smith (D-Sully), who said the two-hour delay was sufficient. Other county lawmakers said it’s better to be safe than sorry.

“There’s a lot of reasons why if we don’t close the schools that day, we’re all going to regret it,” Supervisor Jeff McKay (D-Lee) said. “And, we’re all going to be blamed for it.”