Billionaire businessman Michael Bloomberg is again considering entering the race for the US Democratic party's presidential nomination.

Axar.az reports citing BBC.

The ex-New York City mayor is concerned the current field of candidates is not good enough to beat Donald Trump in the 2020 election, an adviser says.

The 77-year-old is expected to file paperwork on Friday for the Democratic presidential primary in Alabama.

However, he has not yet made a decision on whether to run, advisers add.

If Mr Bloomberg does get on the ballot in Alabama, he will still have to register in other states which have later filing deadlines.

State-by-state votes, known as primaries and caucuses, will be held from February next year to pick a Democratic White House nominee.

The eventual winner will be crowned at the party convention in Wisconsin in July. He or she is expected to face President Trump, a Republican, in the general election in November.

A total of 17 Democratic candidates are vying to be the party's standard-bearer.

Former Vice-President Joe Biden, Massachusetts Senator Elizabeth Warren and Vermont Senator Bernie Sanders are the front-runners.