Washington — Michael Bloomberg is taking steps to enter the 2020 Democratic presidential campaign, a person familiar with his plans tells CBS News.

Bloomberg, 77, has dispatched aides to Alabama to file paperwork in the state to run as a Democrat. The Cotton State doesn't hold an early Democratic presidential primary, but has the earliest filing deadline for the presidential campaign. Taking steps to file paperwork is the most serious signal yet that the former New York mayor and billionaire is seriously planning for a White House run.

The New York Times first reported Bloomberg's plans to file to run in Alabama.

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Howard Wolfson, a longtime Bloomberg adviser, said in a statement that Bloomberg "is increasingly concerned that the current field of candidates is not well positioned" to defeat President Trump.

"If Mike runs he would offer a new choice to Democrats built on a unique record running America's biggest city, building a business from scratch and taking on some of America's toughest challenges as a high-impact philanthropist," Wolfson said. "Based on his record of accomplishment, leadership and his ability to bring people together to drive change, Mike would be able to take the fight to Trump and win."

In an interview with "Face the Nation" moderator Margaret Brennan in late October, Bloomberg expressed his reservations about the Democratic field.

"I have my reservations about the people running and their campaigning, the promises they're making that they can't fulfill, and their willingness to admit what is possible and what isn't and their inconsistency from day to day," he said. "This is not the way to run a railroad."