Hillary Clinton's doctor says the Democratic presidential candidate has been diagnosed with pneumonia, but is "recovering nicely."
Doctor Lisa Bardack made the announcement Sunday after Clinton left a September 11 commemoration ceremony in New York. She stumbled and her knees appeared to buckle as she was helped into her car.
Aides drove her to her daughter Chelsea's New York apartment to rest, and later Clinton emerged looking rested. She hugged a child on the street and waved to supporters.
"I'm feeling great. It's a beautiful day in New York," Clinton said as she left in her car.
Doctor Bardack said the 68 year-old Clinton's unsteadiness was caused by being "overheated and dehydrated."
The doctor examined Clinton Friday for a prolonged cough and she diagnosed pneumonia, a lung infection. She put Clinton on antibiotics and advised her to rest and modify her schedule.
Clinton campaign officials have not yet announced whether any events will be canceled.
Her Republican rival for the White House, Donald Trump, has said Clinton does not have the stamina to handle the presidency. Some of his supporters have tried to make her health a campaign issue.
The 70-year-old Trump released a letter from a physician late last year claiming he would be "the healthiest individual ever elected to the presidency."
But the doctor has since acknowledged he dashed off the note in five minutes while a Trump campaign limousine waited nearby.