Masked visitors enjoy the New Jersey boardwalk on Memorial Day weekend. | Mark Makela/Getty Images

Viral photos of crowds have prompted reminders about the importance of social distancing.

Federal public health officials worked to remind Americans celebrating Memorial Day weekend of the importance of maintaining social distancing Sunday, highlighting that although the coronavirus crisis appears to be gradually improving in many regions of the United States, many still remain at risk of infection.

“With the country starting to open up this holiday weekend, I again remind everyone that the coronavirus is not yet contained,” Stephen Hahn, commissioner of the Food and Drug Administration, tweeted. “It is up to every individual to protect themselves and their community. Social distancing, hand washing and wearing masks protect us all.”

And on ABC’s This Week, Deborah Birx, the White House coronavirus response coordinator, also emphasized the