U.S. Democratic presidential candidate Hillary Clinton climbs into her van outside her daughter Chelsea's home in New York, Sept. 11, 2016, after Clinton left ceremonies commemorating the 15th anniversary of the Sept. 11 attacks feeling "overheated." REUTERS/Brian Snyder

UPDATE: 12:10 a.m. EDT — Hillary Clinton canceled a trip to California over her health issues, a campaign official reportedly said. On Sunday night, it emerged that the Democratic presidential nominee is suffering from pneumonia and has been advised to take rest by her doctor. On Monday and Tuesday, Clinton was scheduled to attend fundraisers in California and tape an episode of the “Ellen DeGeneres Show.”

UPDATE: 6:15 p.m. EDT — Hillary Clinton’s doctor Sunday revealed the Democratic presidential candidate has been diagnosed with pneumonia.

Clinton left the Sept. 11 commemoration ceremony in New York after 90 minutes, complaining of feeling “overheated.” A video showed her slumping and three people helping her get to her van. Dr. Lisa R. Bardack issued a statement saying Clinton had become dehydrated, wire reports said.

“I have just examined her and she is now rehydrated and recovering nicely,” Bardack said.

Clinton is taking antibiotics for the pneumonia and has been advised to rest.

Original story:

Democratic presidential hopeful Hillary Clinton left Sunday’s ceremony marking the 15th anniversary of the Sept. 11, 2001, terrorist attacks in New York after 90 minutes, saying she felt “overheated.”

A spokesman for the Clinton campaign said the former secretary of state retreated to her daughter’s apartment in the Flatiron District and was “feeling much better.” There was no indication whether Clinton, 68, needed medical attention. The New York Times quoted an unidentified official as saying Clinton appeared to have fainted. No reporters were allowed to follow her.

Fox News reported Clinton suffered an apparent “medical episode” and was helped to her van by security personnel.

The weather was described as in the low 80s and humid during the ceremony.

“Secretary Clinton attended the Sept. 11 commemoration ceremony for just an hour and 30 minutes this morning to pay her respects and greet some of the families of the fallen,” spokesman Nick Merrill said. “During the ceremony, she felt overheated, so departed to go to her daughter's apartment and is feeling much better.”

Clinton left her daughter’s apartment without assistance about two hours later, the New York Daily News reported.

“I’m feeling great,” Clinton said before climbing into her van.

Clinton’s Republican rival Donald Trump and his supporters have long tried to cast doubt on Clinton’s health, citing the concussion she suffered in a fall and subsequent blood clot that required her to go on Coumadin, a blood thinner. Her doctor has declared her health excellent.

Following Sunday’s incident, Trump declined to comment.

Talk about Clinton’s health intensified last week following a coughing fit on the campaign trail that an aide attributed to allergies, NBC News reported.

“I’ve been talking so much,” Clinton said with a hoarse voice. “Every time I think about Trump, I get allergic.”

The Washington Post, however, said the coughing fit combined with Sunday’s episode make it impossible for the campaign to laugh off questions about her health.

U.S. Democratic presidential candidate Hillary Clinton leaves ceremonies marking the 15th anniversary of the Sept. 11 attacks at the National 9/11 Memorial in New York, Sept. 11, 2016. Brian Snyder/Reuters