A Patriot Day elbow tap between two political rivals brought cheers from countless social media followers Friday.

Vice President Mike Pence and Democratic White House nominee Joe Biden greeted each other at ground zero in New York City, the site where more than 2,600 people died 19 years ago on Sept. 11. Both were attending the annual memorial service, and their greeting brought a brief-but-touching moment of unity to a nation divided by an election-year global pandemic and unrest over racial and social injustice.

President Donald Trump — the man Biden hopes to replace in the Oval Office in less than eight weeks — and Biden visited the Flight 93 National Memorial in Pennsylvania at different times of day.

Speaking at the Pennsylvania memorial, Trump recalled how the plane’s crew and passengers tried to storm the cockpit as the hijackers headed for Washington.

“The heroes of Flight 93 are an everlasting reminder that no matter the danger, no matter the threat, no matter the odds, America will always rise up, stand tall and fight back,” the president said.

Biden visited the memorial later Friday, laid a wreath and greeted relatives of one of the slain crew members, first officer LeRoy Homer.

In New York, Biden offered condolences to victims' relatives including Amanda Barreto, 27, who lost her aunt and godmother in the attacks. She said Biden “wanted to let me know to keep the faith” and told her he understood what it meant to lose a loved one. His first wife and their daughter died in a car crash, and his son Beau died of brain cancer.

Biden didn’t speak at the ceremony, which has a longstanding custom of not allowing politicians to make remarks.

Pence went on to the separate ceremony, organized by the Stephen Siller Tunnel to Towers Foundation, where he read the Bible’s 23rd Psalm. His wife, Karen, read a passage from the Book of Ecclesiastes.

“For the families of the lost and friends they left behind, I pray these ancient words will comfort your heart and others,” said the vice president, drawing applause from the audience of roughly 200.

Formed in honor of a firefighter killed on 9/11, the foundation felt in-person readers were crucial to the ceremony’s emotional impact and could recite names while keeping a safe distance. By contrast, recorded names emanated from speakers placed around the memorial plaza. Leaders said they wanted to keep readers and listeners from clustering at a stage.

As in past years on the plaza, many readers at the alternative ceremony added poignant tributes to their loved ones' character and heroism, urged the nation not to forget the attacks and recounted missed family milestones: “How I wish you could walk me down the aisle in just three weeks,” Kaitlyn Strada said of her father, Thomas, a bond broker.

One reader thanked essential workers for helping New York City endure the pandemic, which has killed at least 24,000 people in the city and more than 190,000 nationwide. Another reader, Catherine Hernandez, said she became a police officer to honor her family’s loss.

The Sept. 11 memorial and the Tunnel to Towers foundation also tussled over the Tribute in Light, a pair of powerful beams that shine into the night sky near the trade center, evoking its fallen Twin Towers. The 9/11 memorial initially canceled the display, citing virus safety concerns for the installation crew. After the foundation vowed to put up the lights instead, the memorial changed course with help from its chair, former Mayor Mike Bloomberg, and Gov. Andrew Cuomo.

Tunnel to Towers, meanwhile, arranged to display single beams for the first time at the Shanksville memorial and the Pentagon.

Over the years, the anniversary also has become a day for volunteering. Because of the pandemic, the 9/11 National Day of Service and Remembrance organization is encouraging people this year to make donations or take other actions from home.

The Associated Press contributed to this report.