Hillary Clinton's Doctor Says She Has Pneumonia and Became "Overheated and Dehydrated" at 9/11 Memorial

The presidential candidate was observed "fainting" in a departure area.

Hillary Clinton's doctor said in a statement released Sunday afternoon that the presidential candidate has pneumonia and that is why she almost fainted earlier in the day.

Clinton unexpectedly left Sunday's 9/11 anniversary ceremony in New York after feeling "overheated," according to her campaign, and retreated to her daughter's nearby apartment.

Her doctor said she was "overheated and dehydrated."

As she exited the apartment shortly before noon, Clinton said, "I'm feeling great." Clinton spokesman Nick Merrill said in a statement that the Democratic presidential nominee attended the morning ceremony for 90 minutes "to pay her respects and greet some of the families of the fallen."

Continued Merrill: "During the ceremony, she felt overheated so departed to go to her daughter's apartment, and is feeling much better."

The statement offered no additional details, including whether the 68-year-old Clinton required medical attention.

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

A senior law enforcement official who was briefed on the matter said that after leaving the memorial plaza, Clinton was observed "fainting" in a departure area. That official spoke on condition of anonymity, because he wasn't authorized to disclose information publicly.

Clinton walked out of daughter Chelsea Clinton's apartment on her own and made only a brief comment to the reporters waiting outside, saying "It's a beautiful day in New York."

She waved and posed for a photo with a young girl before getting into her motorcade.

Donald Trump supporters have tried to make the case that Clinton is physically unfit for the White House, citing a concussion she sustained in December 2012 after fainting.

Her doctor attributed the episode to a stomach virus and dehydration. Clinton's doctor reported she is fully recovered from the concussion, which led to temporary double vision and discovery of a blood clot in a vein in the space between her brain and skull.

Clinton also has experienced deep vein thrombosis, a clot usually in the leg, and takes the blood thinner Coumadin to prevent new clots.

Trump attended the same memorial service at Ground Zero in lower Manhattan, along with New York's Democratic senators, Chuck Schumer and Kirstin Gillibrand.

The weather was warm and humid in New York on Sunday, and there was a breeze at the crowded memorial plaza during the ceremony.

Clinton's departure from the event was not witnessed by the reporters who travel with her campaign, which did not offer any information about why she left and her whereabouts for more than an hour.

The campaign also did not take reporters in the motorcade after Clinton's departure from her daughter's apartment, and it was unclear where she was headed from there.

Asked after the event about Clinton's health incident, Trump said, "I don't know anything about it." Neither Trump nor Clinton spoke at the event, in keeping with the solemn nature of the annual remembrance of the deadliest terror attack on American soil.

Trump's personal physician has said the Republican presidential nominee is in excellent health both physically and mentally. But the 70-year-old candidate has refused to release his own health records. Dr. Harold Bornstein's report last December remains the only medical information released so far by the Trump campaign.

Bornstein told NBC News he needed just five minutes to write a glowing public assessment of Trump's health as a limousine waited to carry the letter back to Trump.

Initially, Trump said he was unaware of Clinton's situation.

Asked Trump about Hillary Clinton's health incident this morning. He said he didn't know anything about. pic.twitter.com/9zVhLHR0op — Ali Vitali (@alivitali) September 11, 2016

Trump has yet to issue an official response.

Sept. 11, 2:24 p.m.: This story has been updated with a comment from Clinton's doctor.