Alison Friedman this week will become the first of six Democrats running for the nomination to challenge Rep. Barbara Comstock (R-Va.) to begin airing a television ad.

The spot calls for tighter gun laws — a message all of the Democratic hopefuls are hitting hard as they compete for suburban Northern Virginia voters who helped Democrats make big gains in 2017.

Last week, another primary candidate, Army veteran Dan Helmer, released an undercover video of himself legally buying a semiautomatic rifle from a private dealer at a gun show without a background check.

Virginia’s 10th Congressional District is considered one of the most vulnerable in the country and a top target for both parties as Democrats try to take control of the House.

Comstock is seeking a third term representing the district, which stretches from Loudoun County and parts of Fairfax and Prince William to rural counties on the West Virginia border.

In addition to Friedman and Helmer, state Sen. Jennifer Wexton (D-Loudoun) and Obama administration official Lindsey Davis Stover have the resources to run ads in the expensive Washington media market. Former federal prosecutor Paul Pelletier and scientist Julia Biggins are also running.

Friedman has raised the most money among the primary candidates by tapping a network of Hollywood celebrities and national Democrats she met through her work combating human trafficking while she was at the State Department and through her liberal activism.

Her ad, a 30-second spot called “Lockdown,” will begin airing Tuesday, which is five weeks before the June 12 primary.

The ad will air for two weeks on cable television at a cost of $147,000 and broadcast television at a cost of $111,000, according to the campaign.

It was inspired by an email Friedman received in March from her daughter’s school system, warning parents of a potential threat in the age of mass shootings.

“Too many parents know the feeling,” the ad says. “An email from the county. There’s a lockdown. You search for the name of your child’s school and time stops.”

In the ad, Friedman says that “expanding background checks, closing gun show loopholes and banning assault weapons” will make schools safer, and accuses Comstock of selling “our kids’ safety to the NRA.”

Comstock has an “A” rating from the National Rifle Association and ranks 10th among House members who have received the most in donations from the group.