Hillary Clinton told her Twitter followers she is "feeling fine and getting better" on Monday as she fights off pneumonia.
The Democratic presidential nominee's health was called into question after her early exit from Sunday's 9/11 memorial service in New York City. Video taken at the scene showed her looking unsteady and requiring support to enter a van. The campaign said in a statement at the time that Clinton felt "overheated" and went to her daughter Chelsea's Manhattan apartment to rest.
Later that day, Clinton's doctor said she was diagnosed with pneumonia on Friday and suffered from dehydration at the memorial service.
Sunday's episode also sparked criticism of the campaign for not disclosing her medical condition earlier. A spokesman for the campaign told MSNBC on Monday that Clinton would release more medical records this week, adding that she suffers from "no other undisclosed condition."
Republican presidential nominee Donald Trump appeared on CNBC's "Squawk Box" on Monday morning, and questioned the timing of her diagnosis.