Joe Biden on Friday night warned Americans that further restrictions were coming, as the Delta variant causes COVID-19 caseloads across the country to soar.
The president, leaving the White House for a weekend at Camp David, was asked whether new rules were likely to be introduced.
'In all probability,' he said, without expanding.
On Tuesday the Centers for Disease Control and Prevention (CDC) updated its guidance to recommend the wearing of face masks indoors, in areas where there is considerable transmission of the virus.
The new advice applies to both vaccinated and unvaccinated people.
Joe Biden is seen on Friday, during a meeting at the White House. Later in the day he told reporters that 'in all probability' new restrictions would be coming, owing to the rapid spread of COVID-19
To counter the rising raise of infection, the White House is pushing for Americans to get their COVID vaccine but has said repeatedly they won't mandate people get their shot in the arm.
'Yesterday, almost a million people got vaccinated, about half a million people for the first time,' Biden said, calling it 'good news.'
Biden is requiring the more than two million employees of the federal government get vaccinated or submit to regular COVID testing.
The White House has said vaccine requirements are up to private businesses.
On Friday, Disney and Wal-Mart, two of America's largest employers, announced a vaccine requirement for their employees.