A Clinton campaign aide confirmed today that she will be visiting ground zero on Sunday "to pay her respects."
Clinton was in D.C. at the time of the attack as one of New York's senators.
Members of Congress sang "God Bless America" on the evening of Sept. 11 on the steps of the Capitol, and immediately after that, Clinton was interviewed by ABC News' Jonathan Karl, who was working for CNN at the time.
"I don't think we even have an inkling of the devastation," she said in the interview.
"I'm very proud of New York City, the mayor, the police, the fire — all the people working in the emergency front lines have done a superb job. But you know, New York is the global city. It is the symbol of American leadership, and these terrorists made a direct hit on who we are as a people, and New York has responded, and the national government has to stand behind us," she said.
There is footage of Trump doing a video interview with a German news station near ground zero a day later.
"I've never seen anything like it — the devastation, the human life that's been just wasted for no reason whatsoever. It is a terrible scene. It's a terrible sight. But New Yorkers are very strong and resilient, and they'll rebuild quickly," he said during the interview.
On the day of the attacks, Trump has said, he was in his Manhattan apartment.
"I have a window in my apartment that specifically was aimed at the World Trade Center, because of the beauty of the whole downtown Manhattan. And I watched as people jumped, and I watched the second plane come in," he said during a campaign stop in Columbus, Ohio, in November 2015.
"Many people jumped, and I witnessed that. I watched that," he said.
Trump's claim that he saw television reports of people in New Jersey celebrating the attacks has been discredited.
He stood by that claim on the campaign trail last year.