Trump, Biden tear into each other

On the COVID-19 pandemic, Biden said, "It is what it is because you are who you are. He (Trump) knew all the way back in February how deadly it was. You don't panic. He panicked."

"This is his economy. How many of you got up this morning and had an empty chair because of COVID?" Biden said. "His own CDC director says we could lose as many as another 200,000 by the end of year."

"This guy will close down the whole country," Trump said in reference to the pandemic. "We don't need someone to come in and say, 'Let's shut it down.'"

"Far fewer people are dying," the president said. "They give you good press, they give me bad press."

A New York Times report on Sunday claimed that the president avoided federal taxes and has racked up more than $400 million in debt.

The Times' findings also said Trump paid only $750 a year in federal income taxes in 2016 and 2017, and no income taxes in 10 of the previous 15 years.

"This guy paid a total of $750 in taxes," Biden said during the debate, comparing Trump's tax payments with those of a schoolteacher.

Trump, 74, dismissed the Times' report as "fake news" at a news conference on Sunday and in a series of tweets on Monday.

Biden, 77, and his running mate, US Senator Kamala Harris of California, 55，on Tuesday released their 2019 tax returns, which showed that the Democratic presidential nominee and his wife Jill paid close to $300,000 in federal taxes last year.

A Wall Street Journal/NBC News poll released on Sept 16 found that 51 percent of registered voters nationally say they would vote for Biden, while 43 percent back Trump, a tally that was largely unchanged from a month ago.

More than 70 percent say the debates won't matter much to them, and only 11 percent in the survey said they were undecided.

"As fascinating as the Times reports have been, I don't think they will change the basic shape of the race, except that Trump is behind and he needs to start making up ground," said Cal Jillson, a political scientist and historian at Southern Methodist University in Dallas.

"I don't think that these tax returns will have a major impact. This is a character issue, and most voters have already made up their minds about Trump's character and Biden's," said William Galston, a senior fellow at the Brookings Institution's Governance Studies Program who has worked on six Democratic presidential campaigns.

There are two more presidential debates, on Oct 15 and Oct 22, and one vice-presidential debate, on Oct 7.