WASHINGTON -- Ex-U.S. President Donald Trump is likely to make a bid to return to the White House in 2024, but probably won't face off against incumbent Joe Biden, former Trump adviser Jason Miller said.

Trump "has not told me that he has made a decision yet, but in hearing him talk, in hearing the way that he's passionate about helping people and saving America, I can draw the conclusion that I believe that he does run," Miller said in an interview with Nikkei.

Miller said he thinks the Democratic contender for the White House in 2024 will be Vice President Kamala Harris or California Gov. Gavin Newsom, adding a prediction that "ultimately President Trump wins."

A key test for Trump, who has not declared his intentions regarding the 2024 presidential race, will be connecting with voters while being shut out of mainstream social media platforms.

The former president's Twitter and Facebook accounts were frozen after supporters stormed the U.S. Capitol in January. He recently launched a rival platform called Truth Social.

Trump and others have accused Twitter and Facebook of silencing conservative views.

Jason Miller, a former Trump campaign spokesperson, is CEO of new social media platform Gettr.

Trump has not joined Miller's new social media platform Gettr despite months of negotiations to bring him on board, the former aide said.

"We just weren't able to come to terms that we both liked... so we're definitely staying friends, staying allies, but we will be marketplace competitors with regard to the social media business, at least for the near future," said Miller, a former campaign spokesperson for Trump.

Gettr has nearly 3 million users worldwide, according to Miller, who serves as its CEO. About half of all users are based in the U.S., with Japan and Brazil in close competition for the platform's second-largest market, he said.

"Additional countries that we'll start to be very active in will include South Korea, the Philippines, Nigeria, and India," Miller said.

Both Gettr and Truth Social were targeted by hackers around the time of their launches.

Miller described himself as a "conservative Republican" but said "when it comes to the platform, I welcome all political beliefs."

"There are plenty of people who come on the platform every day and criticize me, or criticize President Trump, and they're welcome to do so, as long as they don't violate our terms of service," he said.