Republican presidential nominee Donald Trump has said he "brilliantly used" US tax rules to his advantage in trying to limit the amount he paid in taxes.
He argued that it helped him survive a difficult period in the real estate market.
It was Mr Trump's first extended comments since a New York Times report said he had claimed a $916 million loss on his 1995 tax returns, which experts said might have allowed him to avoid paying federal income taxes for 18 years.
Trump says he used US tax rules 'brilliantly' https://t.co/GUSojjDTFG pic.twitter.com/sUf0BG4Mfd
— RTÉ News (@rtenews) October 3, 2016
"I was able to use the tax laws of this country and my business acumen to dig out of the real estate mess ... when few others were able to do what I did," Mr Trump told a crowd in Pueblo, Colorado.
Hillary Clinton, the Democratic nominee for the 8 November election, has seized on the report, arguing the tax records undercut Mr Trump's business acumen.
"What kind of genius loses a billion dollars in a single year? This is Trump to a T, he's taken corporate excess and made a business out of it," Mrs Clinton told a rally in Toledo, Ohio.
Mrs Clinton has repeatedly called on Mr Trump to release his full returns, as presidential candidates have done in the past.
Mr Trump was dismissive of the Times' story in his Pueblo remarks, saying the media was "obsessed with an alleged tax filing from the 1990s".
The Trump campaign has not said, however, that the Times' story was inaccurate.
Trump Foundation ordered to cease NY fundraising
Meanwhile, the top state prosecutor in New York has ordered Mr Trump's charitable foundation to stop fundraising in New York immediately, saying that it was operating without proper certification.
The office of Attorney General Eric Schneiderman told the Donald J Trump foundation last Friday that it must "cease and desist from soliciting contributions" in New York.
The notice was made public today.
The notice of violation informed the charity that it had been engaged in fundraising activities that were not permitted under the law because they had not been registered with state authorities.
The Trump campaign said in a statement today that the charity would cooperate with the investigation.
"While we remain very concerned about the political motives behind AG Schneiderman's investigation, the Trump Foundation nevertheless intends to cooperate fully with the investigation," said the Trump campaign spokeswoman Hope Hicks.
"Because this is an ongoing legal matter, the Trump Foundation will not comment further at this time," she added.
"Failure to immediately discontinue solicitation ... shall be deemed to be a continuing fraud upon the people of the state of New York," the letter warned.
The notice gave the foundation 15 days to register the required information and file delinquent financial reports of any fundraising activities in previous years with the state's Charities Bureau.
"All forms must be properly certified, complete and accurate," said the letter.
"Any person who swears falsely to any document required ... may be guilty of a crime under the New York Penal Code," it added.
Mr Schneiderman, who is a Democrat, filed a lawsuit in 2013 against the real-estate tycoon accusing his now defunct, self-styled Trump University of being an elaborate scam.
A trial into alleged malpractice at Trump University is scheduled to begin in San Diego, California on 28 November - three weeks after the US presidential election between Mr Trump and his Democratic opponent Hillary Clinton.
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Meanwhile, the US presidential race tightened in a number of traditional battleground states, according to the latest Reuters/Ipsos States of the Nation project poll.
The project poll uses a national online opinion poll of more than 15,000 people per week.
The poll showed that, as of Thursday, Mrs Clinton and her Republican rival were running nearly even in support in Florida and Ohio: states where she had held an advantage.
Arizona, where Mr Trump had held an advantage, was also considered a toss-up.
Meanwhile, Maine, Oregon and Pennsylvania were considered states that Mrs Clinton would likely win.
They had previously been considered toss-ups.
Overall, the poll showed that Mrs Clinton continued to hold the advantage over Mr Trump in the Electoral College, the body that ultimately picks the president.
If the US presidential election were held today, Mrs Clinton would lead Mr Trump 246 to 180 in the Electoral College, and had an 88% chance of gaining the 270 electoral votes needed to become the US chief executive.
A separate Reuters/Ipsos online poll showed that a majority of Americans felt that Mrs Clinton won last week's presidential debate.
Over the past several weeks, the Democrat had maintained a lead of four-five percentage points in support over Mr Trump among likely voters.
