People wear face masks at The National September 11 Memorial & Museum in World Trade Center as the city continues Phase 4 of re-opening following restrictions imposed to slow the spread of coronavirus on July 31, 2020 in New York City.

Americans are commemorating 9/11 with tributes that have been altered by coronavirus precautions and woven into the presidential campaign, drawing both President Donald Trump and Democratic challenger Joe Biden to pay respects at the same memorial without crossing paths.

In New York, a dispute over coronavirus-safety precautions is leading to split-screen remembrances Friday, one at the Sept. 11 memorial plaza at the World Trade Center and another on a nearby corner. The Pentagon's observance will be so restricted that not even victims' families can attend, though small groups can visit the memorial there later in the day.