MCLEAN, VIRGINIA (REUTERS) - President Joe Biden said on Tuesday (July 27) his administration is considering whether to require US federal employees to be vaccinated against Covid-19.

"That's under consideration right now," Biden told a reporter who asked whether the administration was weighing such a requirement.

Biden made the remark during a visit to the Office of the Director of National Intelligence in McLean, Virginia, as his administration's health experts advised Americans fully vaccinated against Covid-19 to start wearing masks again in some circumstances due to the virus' fast-spreading Delta variant.

The White House has told its staff to start wearing masks again, a White House official said on Tuesday.

White House press secretary Jen Psaki said on Monday that the administration had not made a determination about whether it would be legal for Biden to require federal employees to be vaccinated. The US federal government is the country's largest employer.

Biden plans to announce "next steps" on Thursday in the effort to get more Americans to receive shots, the president said in a separate statement released by the White House.

"In the meantime, more vaccinations and mask wearing in the areas most impacted by the Delta variant will enable us to avoid the kind of lockdowns, shutdowns, school closures and disruptions we faced in 2020," he said.

"Unlike 2020, we have both the scientific knowledge and the tools to prevent the spread of this disease. We are not going back to that."

The new health guidance from the US Centres for Disease Control and Prevention applies to fully vaccinated Americans in indoor public places only in regions where the coronavirus is quickly spreading.

Biden said he "certainly will" follow the guidance when he travels to such areas.