Kamala Harris, Donald Trump shake hands again at 9/11 anniversary ceremony

Vice President Kamala Harris and former President Donald Trump shook hands again Wednesday morning as they arrived at the 9/11 anniversary ceremony in downtown Manhattan.

Harris, who was standing between New York Sen. Chuck Schumer and President Joe Biden, reached over the president to shake hands with Trump, who was standing next to former New York City Mayor Michael Bloomberg, after Harris appeared to be prompted by Bloomberg.

Trump described the exchange as "very polite" when he was asked about it later in the day during his visit to the Shanksville Volunteer Fire Department in Shanksville, Pennsylvania. He did not reveal what the two candidates said to one another.

Vice presidential nominee Sen. JD Vance, who was standing next to Trump at the time, told Fox News the handshake was "cordial and polite."

The greeting came less than 12 hours after Harris and Trump met for the first time at a presidential debate in Philadelphia, hosted by ABC News.

Tuesday night's handshake between Harris and Trump ended an eight-year streak of no handshakes on the presidential debate stage. There are no rules or stipulations requiring a handshake before or after the debate.

After the Ground Zero ceremony, Biden and Harris attended 9/11 commemorations at Shanksville and the Pentagon.

"On this day 23 years ago, terrorists believed they could break our will and bring us to our knees. They were wrong. They will always be wrong," Biden said in a statement. "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."

"Today, our longest war is finally over. But our commitment to preventing another attack on our people never will be," he said.

ABC News' Soorin Kim, Kelsey Walsh and Hannah Demissie contributed to this report.