Democratic presidential candidate Hillary Clinton, who was seen staggering into a van after abruptly leaving the 9/11 ceremony in lower Manhattan on Sunday, had been diagnosed with pneumonia days earlier, according to her campaign.

Late Sunday night, The Associated Press reported Clinton had canceled a two-day West Coast campaign trip.

A video Sunday showed Clinton, 68, on a sidewalk swaying and stumbling as her entourage of aides and Secret Service agents grabbed her under the arms and whisked her into a large black van. At the ceremony, her aides wouldn’t confirm her whereabouts to reporters.

Clinton’s campaign on Sunday morning said the candidate had felt “overheated.” Hours later, it released a statement from Clinton’s physician, Dr. Lisa R. Bardack, saying Clinton had been diagnosed with pneumonia on Friday.

“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. 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 rehydrated and recovering nicely,” Bardack said in the statement, which was released at 5:19 p.m. Sunday.

After leaving the ceremony, Clinton went to recover at daughter Chelsea Clinton’s Manhattan apartment, emerging at about 11:45 a.m. smiling, greeting a girl who ran up to her, and saying: “I’m feeling great, I’m feeling great.”

Republican presidential candidate Donald Trump said he hopes Clinton “gets well soon.”

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“Something’s going on, but I just hope she gets well and gets back on the trail and we’ll be seeing her at the debate,” Trump said in an interview on “Fox & Friends” Monday morning.

The first of three presidential debates is scheduled for Sept. 26 at Hofstra University.

Clinton’s camp has been fending off questions about the candidate’s health for months — many of them posed by conservative news outlets, supporters of Trump, and Trump himself, who has knocked Clinton for having “no stamina.”

At a rally last week in Cleveland, Clinton had a brief coughing fit on stage. She joked that she was “allergic” to Trump.

Clinton suffered a concussion in 2012 after falling in her Chappaqua home, and was later hospitalized with a blood clot resulting from the concussion.

Her campaign has fervently denied any issues with her health.

Bardack, who is director of internal medicine at Mount Sinai Health System at CareMount Medical, released a statement Aug. 16 refuting fake medical records circulating on social media and conservative websites.

“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,” Bardack had written.

Sunday morning, Clinton was seen at Ground Zero speaking to officials such as Sen. Chuck Schumer (D-N.Y.) and FDNY Commissioner Daniel Nigro.

Rep. Peter King (R-Seaford) said he greeted Clinton with a handshake and kiss before the ceremony.

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“It was not hot,” he said in an interview. “There was a breeze down there. No one was talking about” the weather.

He said he noticed Clinton leaving the area where the names of the dead were being read at about 9:30 a.m. Her campaign said the candidate had stayed for 90 minutes.

King said Clinton should release her medical records. “Listen, it could be bad luck. But if it happens at a national event, it raises questions. It’s important for her to get it off the table,” he said.

He added that Trump, who is 70, also should release his medical records. “If you’re asking of one, then everyone should,” King said. The Republican presidential candidate, who also attended the 9/11 ceremony on Sunday, has tweeted that he would release detailed medical records if Clinton does.

With AP, Alison Fox and Emily Ngo