Clinton didn't think pneumonia a big deal

Democratic presidential candidate Hillary Clinton says she's feeling better since falling ill at a September 11 memorial ceremony and didn't think her pneumonia diagnosis was significant enough to disclose beforehand.

"I just didn't think it was going to be that big a deal,'' she said of the pneumonia diagnosis she received on Friday.

She told CNN that despite doctor's orders to rest for five days, she thought she could "just keep going forward and power through it and that didn't work out so well.''

Clinton abruptly left the ceremony and appeared to stumble while she was waiting for her motorcade. Asked whether she fainted, Clinton replied: "No, I didn't. I felt dizzy and I did lose my balance for a minute. But I got in, once I could sit down, once I could cool off, once I got some water, I immediately started feeling better.''

She later told supporters via text message and Facebook, "I'm feeling fine and getting better,'' adding, "Like anyone who's ever been home sick from work, I'm just anxious to get back out there.''

Clinton's evening interview, in which she promised to release more information at some point, came as her campaign scrambled to head off lasting damage from a difficult weekend.

Aides are promising to release more of her medical records following her bout of pneumonia and conceding they were too slow in providing information about her condition.

Republican presidential candidate Donald Trump said he hoped his Democratic rival "gets well soon".

"Something's going on, but I just hope she gets well and gets back on the trail, and we'll be seeing her at the debate," he said.

The billionaire real estate tycoon has brought up Clinton's state of health often in campaign stops, arguing that she doesn't have the "strength and stamina" to be president.