Hillary Clinton on Sunday abruptly left a ceremony in New York marking the 15th anniversary of the Sept. 11 attacks, and a video appeared to show her struggling to maintain her balance as a pair of Secret Service agents lifted her into a van. The incident, according to a statement from her physician, was related to pneumonia and dehydration.
“Secretary Clinton has been experiencing a cough related to allergies. On Friday, during follow up evaluation of her prolonged cough, she was diagnosed with pneumonia,” said Dr. Lisa R. Bardack, who examined Mrs. Clinton at her house in Chappaqua on Sunday. “She was put on antibiotics, and advised to rest and modify her schedule. While at this morning’s event, she became overheated and dehydrated. I have just examined her and she is now re-hydrated and recovering nicely.”
Mrs. Clinton was taken from the morning event at ground zero to the Manhattan apartment of her daughter, Chelsea. About 90 minutes after arriving there, Mrs. Clinton emerged from the apartment in New York’s Flatiron district and waved to onlookers, posing for pictures with a little girl on the sidewalk.
“I’m feeling great,” Mrs. Clinton said. “It’s a beautiful day in New York.”
Mrs. Clinton left in her motorcade without the group of reporters that is designated to travel with her in public. A campaign spokesman, Nick Merrill, indicated that she returned to her Chappaqua, N.Y., residence after 1 p.m., but did not give an exact time.
Mr. Merrill described the Democratic presidential nominee as feeling “overheated” during the commemoration ceremony.
But a video of Mrs. Clinton taken by an attendee appears to show her legs buckling as she struggles to steady herself and walk toward her waiting van. She requires assistance from two Secret Service agents, who held her on either side, to get off a curb and into the van. Close-up images revealed her feet were dragging as she was hoisted into the vehicle.
Mrs. Clinton arrived at the commemoration event around 8 a.m. and left at about 9:30. But for over an hour after that, her campaign would not offer any information about why she had left early or where she was.
Mr. Merrill did not respond to multiple inquiries about whether Mrs. Clinton was treated by a doctor or took any medications.
“During the ceremony, she felt overheated, so she departed to go to her daughter’s apartment, and is feeling much better,” Mr. Merrill said.
Donald J. Trump, the Republican presidential nominee, also attended the event, as did a host of other dignitaries. Temperatures were in the high 70s on Sunday morning in New York, and it was humid.
Others at the event said afterward that Mrs. Clinton did not appear ill when she first arrived at the former site of the World Trade Center.
“She seemed fine,” said Representative Peter T. King, Republican of New York, who recalled greeting and speaking briefly with the former secretary of state around 8:30 a.m.
But about an hour later there was a minor commotion, Mr. King said. A number of New York’s current and former elected officials had been standing in silence as the names of the victims of the attacks were read. Suddenly, Mrs. Clinton, herself a former New York senator, left her position.
Senator Chuck Schumer, Democrat of New York, who was standing alongside Mrs. Clinton, indicated that she was not carried away. “It was pretty hot out there, but she seemed fine to me, and left on her own accord,” Mr. Schumer said in a statement, recalling that he and Mrs. Clinton had “chatted for quite a while about our remembrances of Sept. 11 and our families.”
Mr. King said it was hot enough that officials working at the event offered the dignitaries bottles of water as they stood. But he noted that he did not see anybody accept a bottle.