US Democratic presidential candidateHillary Clinton(C) arrives at a ceremony marking the 15th anniversary of September 11 attacks at the National 9/11 Memorial, in New York, theUnited States, on Sept. 11, 2016. The United States on Sunday commemorated the 15th anniversary of the 9/11 attacks.[Photo/Xinhua]

WASHINGTON -- In-depth medical records of US Democratic presidential nominee Hillary Clinton were released on Wednesday, showing her physical conditions are good.

"She continues to remain healthy and fit to serve as President of the United States," said Dr. Lisa Bardarck, Clinton's personal doctor.

The former US secretary of state fainted at a 9/11 memorial ceremony on Sunday and has since stayed home.

Bardarck said the former secretary of state suffered from a "mild, non-contagious bacterial pneumonia."

The rest of the physical exam "was normal and she is in excellent mental condition," Bardarck said in a letter to the media, saying that she examined Clinton several times this week.

"My overall impression is that Mrs. Clinton has remained healthy and has not developed new medical conditions this year other than a sinus and ear infection and her recently diagnosed pneumonia," she wrote.

The Democratic nominee is expected to return to the campaign trail on Thursday and due in several battleground states next week, said her campaign team on Wednesday.

Clinton's Republican rival Donald Trump will also reveal the results of his own recent medical exam during a TV show set to be aired on Thursday, said a daily report by The Hill, a top US political website.

A video of Clinton's faint at Ground Zero on Sunday has returned the issue of health transparency to the central stage in the two candidates' White House bids.

Clinton was diagnosed with pneumonia two days before she fainted on Sunday but her campaign team had kept it quiet until the video was put online.

The September race is unexpectedly rough for Clinton. A series of national poll results showed that her lead over Trump has been narrowed since Labor Day.