Drivers in Manassas snapped up a thousand free COVID-19 tests within hours on Tuesday, underscoring the pent-up demand for testing and the limited supply that continues to delay efforts to safely reopen Northern Virginia.

“By 11 o’clock we already had 1,000 people who had wanted testing, so we had to cut off the line then,” said Amanda David, who coordinates emergency preparedness and response for the Prince William Health District. “But everyone got a ticket that indicated that they were in the first 1,000. With that, they were able to come back between 11 a.m. and 6 p.m. when we closed up shop.”

A similar scene played out in Woodbridge Monday and could repeat itself in Leesburg when free testing opens for one day Wednesday at the Philip A. Bolen Memorial Park. More testing sites are planned for Fairfax County and Alexandria in the coming days.

The demand shows the urgent need for testing in Prince William County and other parts of Northern Virginia. The region is currently under an extended stay-at-home restriction even as other parts of the state moved to a “Phase One” partial reopening last week. Leaders from the region, including Prince William County Board of Supervisors Chair Ann Wheeler, requested the delay from Gov. Ralph Northam (D). In their letter, they said their counties and cities had not reached the key metrics for safely reopening businesses, including expanding testing.

The Prince William Health District has about 4,800 COVID-19 cases, which is about 15 percent of Virginia’s caseload.

Craig Fifer, spokesman for the city of Alexandria, said the significance of the testing sites was not their price, but, rather, their rules.

“These tests do not require symptoms, doctors orders or referrals, or appointments,” he said. “Virtually all testing in Alexandria so far has required symptoms and most have required either a referral, an appointment, or both.”

The Fairfax County testing sites will be in Annandale and Bailey’s Crossroads, two areas that have been hard hit by COVID-19, said Tina Dale, a spokeswoman with the Fairfax County Health Department.

The free, accessible testing comes after some state lawmakers and activists demanded the state provide more support to stem the spread of the virus. In particular, they noted, the virus was prevalent among uninsured low-income residents who could not afford to get doctors’ referrals.

Luis Aguilar, director of the immigrant advocacy group CASA Virginia, offered limited praise for the testing.

“We welcome that and hope they continue increasing this,” he said in an e-mail to  DCist/WAMU. “We also hope they use messaging that is inclusive and ensures folks that immigration status will not be an obstacle.”

State Sen. Scott Surovell (D-Fairfax) said the health department should also distribute masks and operate a mobile clinic in the D.C. suburbs.

“While I think that having a couple thousand free tests here and there across Northern Virginia over the next few weeks is real progress,” he said, “I do think we can do better than that.”

Nevertheless, the tests are a help. David in Prince William County said this is the first time the county was able to offer free testing for the coronavirus. The Virginia Department of Health paid for the tests, Mako Medical Laboratories provided them, and Prince William County arranged testing sites and protective equipment, David said.

The pop-up testing sites only run for a day at a time. David said her health district primarily focuses on supporting free clinics and private organizations that do testing, rather than run its own testing program. Still, help from the Virginia Department of Health has been more forthcoming, she said. She says the Prince William Health District separately arranged for an additional 750 tests from VDH for later in the week.

Asked if those would satisfy the need, David answered, “those 750 tests are more than we had before.”