HOUSTON — US billionaire Michael Bloomberg has launched a charm offensive to convince black voters, an important bloc in Democratic politics, that he is the right candidate to take on President Donald Trump in November.

The former New York mayor rallied supporters in Texas on Thursday, with his sights set on so-called "Super Tuesday" on March 3, when voters in 16 states and territories will cast their ballots in the Democratic primary.

It is Bloomberg's sixth visit to the Lone Star state since he entered the race to be the party's presidential candidate.

"This month, we look back and celebrate black history together, because black history is American history," Bloomberg said at the Buffalo Soldiers museum, named after a Civil War regiment of African-American soldiers, where he kicked off his "Mike for Black America" campaign.

With 19 campaign offices and 150 employees in Texas he now has a larger presence than any other candidate in the state.

Texas is key to the Democratic primaries because it has such a large number of delegates, 228, more than the total of all the other states that vote in February, where the billionaire chose not to run.

If a candidate obtains a majority of delegates, or 1,991, he or she will take on Trump in the presidential election.

Bloomberg has thrown large amounts of money from his personal fortune into the campaign — spending more than $300 million across the country and about $29 million in Texas alone, according to the Kantar/Campaign Media Analysis Group.

The 77-year-old's campaign in the state has focused on black voters, who will be key to deciding the Democratic nomination.

When he first visited Houston at the end of January, Bloomberg spoke of an economic program aimed at black business people and home-owners.

On Thursday he again apologized for backing arbitrary "stop-and-frisk" searches by the New York police when he was mayor.

"I defended it, looking back, for too long, because I didn't understand then the unintended pain it was causing to young black and brown families and their kids".

Bloomberg had already apologized over the scandal, but it surfaced again after a recording was spread widely on social media — and retweeted by Trump — in which he said police should be deployed to minority neighborhoods because "that's where all the crime is."

He received the support Thursday of the influential, black Democratic mayor of Houston, Sylvester Turner.

"It's important for me to hear the recognition that the policy that was put in place was not the right policy, that it was flawed, that it was insensitive," Turner said.

"You don't judge the people by the mistakes they make, you judge people by their ability to fess up and then work collectively to move you forward."

The scandal did not appear to have put off his supporters however.

"I really have been impressed how he was very apologetic on the mistake that he made," said Yolanda Richard, who came to listen to Bloomberg speak.

"It takes a lot to come back and stand before people and apologize and admit he was wrong."

Although Bloomberg has yet to put himself to the vote in a Democratic primary, he is rising briskly in the polls and in third place on average country-wide.

Some, like retiree Niiobli Armah, think Bloomberg is the person to beat Trump.

"We've all seen what has been going on in this country, we know what has been going on in the White house, and we really need an alternative." — AFP