The Pima County Health Department issued a voluntary curfew Monday as the county remains in a state of substantial spread of coronavirus, according to a media release from the department.

Individuals are asked to observe the curfew from 10 p.m. to 5 a.m. every day until Dec. 31 after Pima County reported its highest daily case count of 878 on Sunday.

The week of Nov. 16 saw the highest weekly case count of 2,575, and now the health department is asking all Pima County residents to stay indoors during the curfew, “except those individuals who have no fixed address,” according to the release.

The health department says residents are allowed to leave home for essential activities like attending work or obtaining food or medical care.

"It is necessary to take this additional step due to the accelerating nature of the pandemic in our community," Pima County Health Director Theresa Cullen said in the release. "While we appreciate the efforts of the majority of residents to slow the spread of the virus, a segment of the population continues to participate in social gatherings and resist the use of masks which exacerbates an already critical situation."

In addition to voluntarily adhering to the curfew, the health department is asking residents to continue wearing a mask, social distancing and frequently sanitizing.