"Did you see what's happening with Biden? He's a corrupt politician," Trump said in Carson City, Nevada on Sunday night.
When one supporter yelled "lock her up" in an apparent reference to Hillary Clinton, Trump stopped and corrected, "no, lock him up."
"Joe Biden is and always has been a corrupt politician," Trump declared. "He always has been. And as far as I'm concerned, the Biden family is a criminal enterprise. It really is."
Trump fired several shots at his 2020 Democratic opponent in his speech Sunday, during which he repeatedly praised the New York Post for their explosive report detailing allegedly corrupt business deals by Joe Biden's son Hunter Biden.
At one point, Trump appeared to mock Biden for urging him to "listen to the scientists" in his handling of the coronavirus pandemic, telling the crowd, that "If I listened to the scientists, we would have a country right now that would be in a massive depression.
"Now," Trump added, "We're like a rocketship. Look at the [economic] numbers."
Biden campaign spokesperson Andrew Bates responded to the president's remarks late Sunday, telling Fox News in a statement that "Donald Trump tanked the strong economy he inherited from the Obama-Biden Administration by continually discounting and attacking warnings from the scientific and medical experts working around the clock to save lives."
"Now," Bates said, "new coronavirus cases are surging and layoffs are rising. If Donald Trump had listened to Joe Biden when he urged him not to trust the Chinese government over his own scientific advisers about this crisis, he wouldn't be the worst jobs president since 1929."
Trump returned to the campaign trail last Saturday after recovering from the coronavirus, which required a three-day hospital stay at Walter Reed Medical Center.
With just 16 days to the election, the president plans to spend much of this week campaigning, with scheduled rallies in Prescott and Tucson, Arizona, on Monday, and rallies later in the week in Erie, Pennsylvania, and Gastonia, North Carolina.