US President Donald Trump said he felt good about his chances for victory as the US election opened on Tuesday, predicting that he would register big victories in key states such as Florida and Arizona.

“We feel very good,” a hoarse-voiced Trump told Fox News in a phone interview. “I think we'll have victory.”

Trump said he expected victory in all the key states that will decide the election.

“We think we are winning Texas very big. We think we are winning Florida very big. We think we are winning Arizona very big,” he said.

“I think we are going to do very well in North Carolina. I think we are going to do well in Pennsylvania. We think we are doing very well everywhere.“

The US president added he will spend Election Day making phone calls to people who have been loyal to him and will go to his campaign headquarters in suburban Virginia to thank the staff.

Trump said he would declare himself the winner of the election "only when there’s victory”.

There has been concern that Trump will declare victory early — before vote counts are definitive. But the Republican president told Fox there’s no reason to “play games”, adding that he thinks he has a "very solid chance at winning".

Trump also said he understands why businesses are boarding up their storefronts but thinks it’s very sad they feel the need to do it.

Read: FBI warns of possible US election violence in protest-riven Portland

He predicted that if there is violence and unrest, it will be in Democratically run cities like Chicago, New York, Portland, Oakland, and Baltimore and blamed “weak leadership”.