Navajo Nation health officials say two dozen communities on the reservation have uncontrolled spread of COVID-19.
The Navajo Department of Health has issued a health advisory notice for the areas and tribal officials encourage residents to take precautions if they travel off the reservation.
They say when cases increase in towns bordering the Navajo Nation the tribe typically also sees an uptick.
It comes as Navajo officials confirmed 75 new known infections and two deaths over the four-day period that included Memorial Day Weekend.
Arizona health officials have reported a rise in COVID cases in recent weeks from a recent low point in April.
