US President Joe Biden and Vice President Kamala Harris stood alongside former president Donald Trump on Wednesday to observe the 23rd anniversary of the attacks of September 11, 2001, at the site in New York City where hijacked planes were crashed and killed nearly 3,000 people.
Relatives read out the names of those who died at the ceremony at the Ground Zero site, where planes brought down the World Trade Centre's twin towers. The US leaders did not speak at the event.
Ms Harris, the Democratic presidential nominee, and Mr Trump, her Republican rival, appeared together the morning after their contentious debate in Philadelphia, with only eight weeks until the November 5 presidential election.
The two candidates shook hands and spoke before lining up for the commemoration. Former New York mayor Michael Bloomberg also attended, standing between Mr Biden and Mr Trump.
Mr Bloomberg appeared to co-ordinate the handshake between Ms Harris and Mr Trump – their second after the Democrat walked across the presidential debate stage to shake her rival's hand in Philadelphia on Tuesday evening, AP reported.
Mr Biden and Ms Harris attended another memorial in Shanksville, Pennsylvania, where passengers on United Flight 93 overcame the hijackers and the plane crashed in a field, preventing another target from being hit.
Then they went to the Washington area to visit a memorial at the Pentagon in Virginia, which was also hit in the attacks.
“On this day 23 years ago, terrorists believed they could break our will and bring us to our knees,” Mr Biden said in an early morning statement. “They were wrong. They will always be wrong. In the darkest of hours, we found light. And in the face of fear, we came together – to defend our country and to help one another.”
Mr Trump, who also planned to visit the Pennsylvania memorial, told Fox News on Wednesday: “It was very, very sad, horrible day. There's never been anything like it.”
Mr Biden earlier issued a proclamation honouring those who died as a result of the attacks, as well as the hundreds of thousands of Americans who volunteered for military service afterwards, Reuters reported.
“We owe these patriots of the 9/11 generation a debt of gratitude that we can never fully repay,” Mr Biden said, talking of those sent to Afghanistan, Iraq and other war zones, as well as the capture and killing of September 11 mastermind Osama bin Laden and his deputy.
