WASHINGTON (REUTERS) - Billionaire Michael Bloomberg is planning to spend around US$15 million (S$20.4 million) on television advertising in Texas and Ohio during the final week of the presidential campaign to help Democratic candidate Joe Biden defeat President Donald Trump, a Bloomberg spokesperson said on Tuesday (Oct 27).

Statewide ads in Texas and Ohio will run from Wednesday through Election Day next Tuesday.

Mr Bloomberg, the former New York City mayor who lost to Biden in a crowded field for the Democratic nomination, previously vowed to spend up to US$100 million of his personal fortune to support Mr Biden in Florida though his super PAC, Independence USA, and other Democratic groups.

Mr Bloomberg asked his team to see polling data from multiple states and after reviewing the numbers on Monday decided to invest additional money to support Mr Biden in Texas and Ohio, the spokesman said by email, confirming a report in the New York Times.

"We believe that Florida will go down to the wire, and we were looking for additional opportunities to expand the map," Mr Bloomberg aide Howard Wolfson told the Times.

"Texas and Ohio present the best opportunities to do that, in our view."

Mr Bloomberg will also increase pro-Biden advertising in Florida, fortifying a campaign that began mid-September with daily ads in 10 Florida media markets, the spokesperson said.

The Texas ads, in English and Spanish, will focus on Mr Trump's handling of the Covid-19 pandemic, and the Ohio ads will focus on the pandemic plus the economy and Mr Biden's "build back better" theme, the spokesperson said.

Mr Trump won Texas and Ohio in his 2016 election, and holding on to both states is crucial to his re-election prospects. As the second and seventh most populous states, both are prizes in the state-by-state contests that decide the presidential race.