The City of Portland is asking residents to wear masks indoors, with Cumberland County now among the areas in the state experiencing high or substantial levels of coronavirus spread.

Mayor Kate Snyder announced Thursday, the same day updated data from the U.S. CDC placed Cumberland County in the “Substantial” category for virus transmission, that everyone should wear masks in public indoor settings regardless of vaccination status.

The city is also reimplementing mask requirements for staff in city buildings, with Portland City Hall still open to limited in-person services only.

The changes come as the highly contagious Delta variant of the virus continues to spread in Maine and across the nation, mostly among the unvaccinated population.