U.S. President-elect Joe Biden, who plans to make the coronavirus pandemic his top priority, will begin his presidency by asking Americans to wear masks for 100 days and requiring their use on federal property.

His first executive order, the "100 Days Masking Challenge," will symbolize the administration's sharp turn from the Trump era by emphasizing recommendations by public health experts. A president cannot tell states or cities what to do, but a federal mandate will affect federal offices and federal lands and will urge states to do the same.

"This executive action will direct the agencies to take action to require compliance with CDC guidance on mask wearing and physical distancing in federal buildings, on federal lands and by federal employees and contractors," said Biden counselor Jeff Zients, who will be the administration's COVID-19 response coordinator.

"And the president will call on governors, public health officials, mayors, business leaders and others to implement masking, physical distancing and other public measures to control COVID-19," Zients added.

"This is not a political statement. This is about the health of our families, and economic recovery of our country."

President Donald Trump pointedly refused to wear a mask in public throughout his presidency, and Trump political appointees across federal agencies often discouraged mask use among their staff. Largely mask-free events sponsored by the White House were linked to multiple COVID-19 infections, including a party surrounding the swearing-in of Supreme Court Justice Amy Coney Barrett.

Trump was himself hospitalized for a coronavirus infection in the fall.

REJOINING THE WORLD

Biden also plans to try to get the U.S. back into the world arena in fighting the coronavirus pandemic, aides told reporters.

That means an immediate reversal of Trump's decision to leave the World Health Organization, Zients told reporters.

"America's withdrawal from the international arena has impeded progress on the global response and left us more vulnerable to future pandemics," Zients said during a telephone briefing Tuesday afternoon.

"He will take action to cease the previous administration's process of withdrawing from the World Health Organization, and the Biden/Harris administration will participate in the WHO executive board meeting this week."

Dr. Anthony Fauci, who as director of the National Institute of Allergy and Infectious Diseases was the most prominent medical professional speaking about the coronavirus pandemic under the Trump administration, will speak to the WHO executive board in an official capacity Thursday.

Biden will also restore the National Security Council's Directorate for Global Health Security and Biodefense. That office, established in 2015 under the Obama administration, was disbanded in 2018, although the Trump administration denied that meant it had abandoned all pandemic preparedness.

"Moving forward, we will focus on immediate and emerging domestic and global biological threats and play a critical role in stopping this pandemic and preventing future biological catastrophes," Zients said.

It won't be a Day One executive order, but Zients also said the administration will reverse the so-called Mexico City policy -- a policy denying U.S. federal funding to any organizations globally that support abortion rights. The policy, also known as the Global Gag Rule, is regularly reversed by Democratic administrations and restored in various forms by Republican presidents.

Biden will also try to stop evictions related to people's job losses because of the pandemic, said Brian Deese, who will lead the National Economic Council.

"We were heartened to see Congress take a step in the right direction in providing some rental assistance and extending the federal eviction moratorium until January 31. But the threat of widespread evictions still exists at the end of the month in only a few days," Deese said, adding that Biden will ask the CDC to consider extending the federal eviction moratorium until at least the end of March.