The president also claimed during a rally that Democratic nominee Joe Biden would turn Minnesota into a "refugee camp."
Numbers were down 13 percent from the first debate between Trump and Hillary Clinton in 2016.
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A few Republican senators are heavy underdogs in their upcoming elections, according to the betting line.
TikTok, which Trump has been trying to ban in the U.S., was among the social media outlets spreading false report that Joe Biden wore a wire Tuesday.
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Pictures showed Trump's family not wearing masks during the first presidential debate.
Republican President Donald Trump and Democratic nominee Joe Biden are set to square off two more times in October, after a chaotic first debate on Tuesday.
The first presidential debate between Trump and Biden saw both candidates exchanging a series of attacks and name-calling throughout the 90-minute event.
President Trump lost the two states by a slim margin in 2016.
Democratic nominee Joe Biden is nearly tied with Republican President Donald Trump in the traditionally red state of South Carolina, according to a poll released on Wednesday.
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Conservatives also turned their wrath on moderator Chris Wallace, accusing him of siding with Biden.
A federal appeals court on Wednesday blocked a Republican-backed lawsuit in Wisconsin over the state’s extended absentee ballot deadlines, as COVID-19 cases spike.
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The Commission on Presidential Debates said it doesn't want a repeat of Tuesday's chaotic matchup between President Trump and Joe Biden.
Analysts cautioned the looming election and remaining presidential debates could increase volatility in the U.S. market over the next month.
The State Department said it would use its position in the OSCE Minsk Group to help bring leaders from both countries to the table.