WASHINGTON, Sept 28 (Reuters) - A report that Donald Trump paid little or no federal income tax in recent years sparked broad outrage on Monday, from rich Democrats to teachers and coffee shop workers taking to social media to claim they had paid more taxes than the U.S. president.

The #IPaidMoreTaxesThanDonaldTrump hashtag began trending on Monday, while Democratic rival Joe Biden's election campaign seized on the backlash, launching merchandise with the words: 'I Paid More In Taxes Than Donald Trump.'

"It's not fair. If I had to pay taxes, why shouldn't everybody else?" said Reginald Tyson, a retired army veteran, speaking outside the Lincoln Memorial in Washington.

Tom Steyer, a billionaire environmentalist and a fierce critic of the president, took to Twitter to castigate Trump over his taxes and called for voters to kick him out office on Nov. 3. "In 2017, I paid $32 million more in federal taxes than Donald Trump," he added.

Trump defended his record on Monday after the New York Times reported he had paid just $750 in federal income taxes in both 2016 and 2017, after years of reporting heavy losses from his business enterprises.

In a series of Twitter posts, the Republican president said he had paid "many millions of dollars in taxes" and that he had many more assets than debt. He did not provide evidence or promise to release any financial statements before the Nov. 3 presidential election.

It is unclear whether the events will affect how Americans vote. Trump's Twitter posts received tens of thousands of 'likes', as his supporters spoke out in his defense.

George Callas, managing director at law firm Steptoe LLP and former Republican tax counsel in the U.S. House of Representatives, criticized in a tweet the leaking of confidential tax information and defended the tax system, while acknowledging some wealthy people avoid paying much, if any, tax.

"There is nothing inherently 'unfair' about using losses to offset income. In fact, it's a critical piece of measuring someone's actual income over time," he wrote in a follow-up email to Reuters. "The question is whether those losses are real economic losses or just paper losses generated for tax purposes. And that can be very difficult to tease out."

Polly Hartsook, 68, who runs a farm with her husband in Ringgold County, Iowa, said the tax system was written to help "job creators."

"My guess is Donald Trump didn't prepare his tax returns, his tax preparers did it," said Hartsook, who said she voted for Trump in 2016 and will do so again. "Rather than give his money to the Treasury, Trump reinvests his money in things that provide jobs."

For others, the idea that the real estate mogul had paid so little in taxes touched a nerve.

Amy Grandinetti, 48, a nurse from Columbus, Ohio, who said she was backing Biden in November, described Trump's tax avoidance as "insane."

"This should give serious pause to the average American," she said.

Connor Madan, 23, from Washington, likewise balked at Trump's reported taxes, adding: "I feel like I pay more taxes than the president has. He's supposed to be setting the example for everyone." (Additional reporting by Krystal Hu, Deborah Gembara; Julio-César Chávez and Josh Franklin; Writing by Paritosh Bansal; Editing by Rosalba O'Brien)