Former President Donald Trump on Monday said he expected President Joe Biden's fall while boarding Air Force One ahead of his Atlanta trip.

In a Newsmax interview on Friday, Trump also said that he believed that Vice President Kamala Harris might replace Biden because the president's mental state is declining and may come to a point he may not understand what he signs.

"There's something going on, it's crazy. What's happening is crazy and you wonder whether or not all of the things that he's signing, whether or not he understands what he's signing," Trump said.

New York Post reported that during the presidential campaign last year, Trump repeatedly said that the 78-year-old president "gone" mentally. He also taunted that Democrats were interested in replacing Biden with Harris shortly after the election using the 25th Amendment.

Trump told Newsmax host Greg Kelly that he still believes it can still happen, citing the president's gaffe in which he addressed Kamala Harris as "President Harris."

The former president has also raised questions on media's reporting regarding Biden's fall on Air Force One's stairs. According to an Independent report, Trump has called the incident terrible and claimed that the media had ignored it for the most part.

When asked if he was shocked by the apparent media "disparity," Trump said he expected it. Some compared the Biden's fall to an incident where Trump walked slowly down a ramp after delivering a graduation speech at West Point in June last year.

The former president said he wanted to go inch by inch when he went down the ramp at West Point, which he compared to a sheet of ice with no railing, because "the last thing I wanted to do was take a tumble like Biden did."

Biden stumbled three times up the stairs of Air Force One on Friday. He initially tried to gather himself, only to stumble again on the presidential plane's steps.

The White House blamed the wind and immediately said that the president is doing 100 percent fine after his fall, Fox News reported.

"I know folks have seen that President Biden slipped on his way up the stairs to AF1, but I'm happy to report that he is just fine and did not even require any attention from the medical team who travels with him," said White Communications Director Kate Bedingfield, adding that it was just a misstep on the stairs.

RELATED ARTICLE: Biden Stumbles on Steps of Air Force One Before Atlanta Trip

Donald Trump's Response

In a video clip that surfaced on social media Saturday, Trump told an audience that as he watched Biden went up the stairs, he said, "I didn't lose to him'," Biz Pac Review reported. 

Meanwhile, the White House has yet to comment on Trump's reaction regarding Biden's fall. Trump was not the only one who mocked Biden. His eldest son, Donald Trump Jr., also took a jab at the president.

Trump Jr. tweeted that it was not the wind and posted an edited video that made it look like his father hit and knocked down Biden with a golf ball, Washington Examiner reported.

The younger Trump went on to say that he remembered when the press bashed his father for touching the rail once.

Biden earlier mocked Trump for slowly walking down the ramp at West Point, saying: "Look at how he steps and look at how I step... Watch how I run up ramps and he stumbles down ramps. OK? Come on."

READ MORE: 'Something's Not Right' With Biden's Health, Former White House Physician Says

WATCH: Trump Jr. Shares Edited Video Showing Father Knocking Biden Down With Golf Ball - From Cobrapost