Billionaire former New York City Mayor Michael Bloomberg has signalled that he would join the race to secure the Democratic Party’s nomination for US president. He has filed paperwork ahead of a deadline for the Democratic primary election in Alabama.

The move is a necessary step to join the race to be the party’s candidate to take on President Donald Trump in next year’s election.

Mr Bloomberg, 77, has not formally confirmed his candidacy. However, spokesman Jason Schechter told US media that an announcement “could come as early as next week”.

The businessman is said to be concerned the current Democratic contenders would not pose a strong enough challenge to Mr Trump in 2020, as reported by BBC. He will be entering a crowded field as one of 17 candidates hoping to be chosen as the Democratic nominee.

Former Vice President Joe Biden is the frontrunner, followed by senators Bernie Sanders and Elizabeth Warren.

The tycoon had strongly hinted that he would run, with his adviser Howard Wolfson releasing a statement on Thursday evening saying they wanted to “ensure that Trump is defeated” in the election next year.