CHARLOTTE, N.C. — As key Democratic figures coalesced behind Joe Biden, President Donald Trump lobbed an extended attack at the former vice president at a rally here hours before the Super Tuesday contest.

Seeking to raise doubts about Biden’s acumen, Trump seized on his most recent gaffes, like slipping and referring to Super Tuesday as “super Thursday,” claiming 150 million people were killed by guns since 2007, and saying he was running for Senate rather than the presidency.

“Maybe he gets in because he's a little more moderate," Trump said of Biden. "But he's not going to be running it, other people are going to. They’re going to put him into a home and other people are going to be running the country and they're going to be super left radical crazies.”

Trump’s attacks came as a flock of current and former Democratic Party officials threw their support behind Biden on Monday following his weekend victory in South Carolina, partly in an effort to block Sen. Bernie Sanders, I-Vt., from securing the nomination.

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“You see what's happening right there now, it's being rigged against Crazy Bernie,” Trump said, repeating a common Twitter theme he often deploys in an effort to stoke dissent among Democrats.

Trump’s campaign advisers have acknowledged that Biden could pose a tough match for them in Rust Belt states and among suburban voters. But they also say the former vice president's meandering speaking style and factual stumbles could give voters pause about his acumen and that he lacks voter enthusiasm.

Trump’s speech wrapped shortly before Biden took the stage in Dallas with Sen. Amy Klobuchar, D-Minn., one of the former moderate rivals who withdrew from the race over the past 24 hours and backed him. (Former South Bend, Indiana, Mayor Pete Buttigieg also backed Biden on Monday.) Trump took note of the dual endorsements, suggesting they were part of a backroom deal.

“You know they both supported 'Sleepy Joe,' you know why? They made a deal, you know why? Quid pro quo,” Trump said, joking they should be "impeached" for any possible coordination.

Trump was in the Super Tuesday state of North Carolina hours before the polls opened there as part of a counterprogramming strategy aimed at grabbing attention from Democrats ahead of key moments. Since January, he has held rallies before caucuses and primaries in Iowa, New Hampshire, Nevada and South Carolina. Trump is also on the ballot here Tuesday, and is expected to handily win the Republican nomination.

“We like to troll. We like to go the night before one of their primaries, we just, we do a little trolling,” Trump said.

North Carolina, which he won in 2016 and which will host the Republican convention over the summer, is also one of the Trump campaign’s top priority states.

The president lobbed attacks at nearly all the remaining Democratic contenders — including Sanders, Sen. Elizabeth Warren, D-Mass., and former New York City Mayor Mike Bloomberg — but spent by far the most time on Biden.

Trump used the event to again downplay fears over the coronavirus, as the numbers rose to more than 100 confirmed cases in the United States, with six deaths. Trump again accused Democrats of politicizing the crisis and said a vaccine was on the way, “I think relatively soon," though health officials have said it wouldn’t be available for the public until at least next year.

The threat of the virus didn’t keep crowds away from Monday night’s rally, where people packed a hockey arena here that holds more than 8,000. Trump said earlier in the day at the White House that these large campaign gatherings are considered "very safe."