Democratic presidential candidate Hillary Clinton on Sunday left a remembrance ceremony on the 15th anniversary of the 9/11 attacks early after feeling unwell, U.S. media reported.

Clinton appeared to faint on her way into her van as she was leaving the memorial event, and had to be helped by her security. Fox News cited an unnamed source as saying Clinton was “clearly having some type of medical episode.”

Fox News quoted the source saying Clinton stumbled off the curb, her "knees buckled" and she lost a shoe as she was helped into a van during her "unexpected early departure."

This video appeared to show the incident, Buzzfeed reported.

Hillary Clinton 9/11 NYC pic.twitter.com/q9YnsjTxss — Zdenek Gazda (@zgazda66) September 11, 2016

CNN and MSNBC quoted a statement from her campaign as saying she "felt overheated" and so left to go to her daughter Chelsea's apartment, where she was "feeling much better."

Just before noon Sunday, Clinton was filmed leaving the apartment and waving to the press and others. She paused briefly, and took a picture with a small child on the sidewalk in front of the apartment.

Clinton leaves Chelsea's apartment after "overheating."



"I'm feeling great, it's a beautiful day in New York." pic.twitter.com/uKUDhDMfBo — David Mack (@davidmackau) September 11, 2016



"Secretary Clinton attended the September 11th Commemoration Ceremony for just one hour and 30 minutes this morning to pay her respects and greet some of the families of the fallen. During the ceremony, she felt overheated so departed to go to her daughter's apartment, and is feeling much better," Clinton spokesman Nick Merrill said in a statement.'

Donald Trump was also in attendance at the event marking 15 years since the terrorist attacks, remaining until later in the morning. When asked about the incident, he said, "I don't know anything about it."

NEW: Trump tells me "I don't know anything about" Clinton's health incident this morning. #nbc2016 pic.twitter.com/FATsLp8i6e — Ali Vitali (@alivitali) September 11, 2016

Clinton's health has been an issue in the campaign in recent months. In December 2012, Clinton, 68, suffered a concussion and shortly afterward had a blood clot.

Trump supporters have actively fanned rumors about her health. In mid-August, Clinton's camp released a statement from her physician, Dr. Lisa Bardack, proclaiming Clinton's "excellent health" while re-circulating a letter describing her health in greater detail.

"To reiterate what I said in my previous statement, Secretary Clinton is in excellent health and fit to serve as President of the United States," she said last month. Clinton herself has always dismissed health questions when asked about them, and her campaign called speculation in the conservative media "deranged conspiracy theories."

Clinton also jokingly addressed the claims on Jimmy Kimmel's ABC late night talk show.

"Back in October, the National Enquirer said I would be dead in six months. So with every breath I take I feel like I have a new lease on life," she said. "I don't know why they are saying this. I think on the one hand, it is part of the wacky strategy - just say all these crazy things and maybe you can get some people to believe you."

Much of the whispering about Clinton's health stems from her December 2012 concussion and ensuing blood clot during the closing days of her tenure at the State Department, Politico and other new sites reported. The conversation re-ignited in recent days after FBI records showed she said she could not recall every briefing she received.

