ROCHESTER – President Donald Trump predicted a "very big surprise" in Minnesota in the upcoming midterm elections as he urged Republicans gathered here Thursday to support candidates who will back his agenda.

"This is supposed to be a Democrat state. … I don't think so," Trump said to loud cheers. He narrowly lost Minnesota in 2016, and the state has a number of competitive, high-dollar congressional elections this year that could determine whether Republicans or Democrats control Congress next year.

"I need your vote. I need your support to stop radical Democrats and to elect proud Minnesota Republicans," the president said, clearly relishing campaign mode. Electing Democrats, he warned, would create "a nightmare of gridlock, chaos and, frankly, crime."

Escalating a full-bore blast at Democrats in remarks that lasted 70 minutes, he called them "truly the party of crime."

The speech at Rochester's Mayo Civic Center drew a capacity crowd of 10,000, with 1,000 to 2,000 more watching on giant screens outside, according to city officials. Huge crowds thronged outside many hours before the rally started, while hundreds marched nearby in protest of Trump's visits. Minnesota Democrats, some of whom ended up on the receiving end of Trump's insults, used the president's visit as a draw for their own get-out-the-vote efforts.

Diane Nagel, a 67-year-old retiree from Owatonna, participated in a protest march hours before Trump took the stage — her first time joining a political demonstration, she said. Nagel said she once voted for Republicans but could no longer do so under Trump.

"The Republican Party has changed a lot," Nagel said. "It's gotten really far right."

Inside the arena, Trump quickly moved through a number of topics.

As the Senate prepares to vote on the nomination of Brett Kavanaugh to the U.S. Supreme Court, Trump called him "one of the most respected people." Democrats, the president said, "are trying to destroy Judge Brett Kavanaugh from the very first second he was announced."

He also launched an attack on Democratic U.S. Sen. Tina Smith, bringing her opponent Karin Housley on stage to speak for a moment and saying that "nobody ever heard of" Smith. Earlier in the day, Smith tweeted about Trump's visit.

"Hope he doesn't get too comfortable. We may be 'nice' in Minnesota but when people like him attack us and our values, we rise up, we fight hard, and we don't back down," Smith tweeted. She also sent out a fundraising appeal after Trump's speech, citing his attack.

Trump also took shots at Al Franken, Smith's Democratic predecessor, who resigned in January after accusations of sexual misconduct, and at Keith Ellison, the DFL candidate for state attorney general. Trump called Franken "a wacky guy" who folded "like a wet rag." Trump blasted Ellison as an advocate of ''open borders,'' but stayed away from the abuse allegation leveled at Ellison by a former girlfriend.

Some in the crowd, however, waved placards depicting Ellison wearing a "wife beater"-style T shirt, with the word "abuse" crossed out underneath. Ellison has denied the allegation. Later Thursday, Ellison said through his campaign that Trump is attempting to divide Minnesotans while Ellison "is focused on defending affordable health care, a fair economy, and equal opportunity.''

Trump summoned two other congressional candidates to the stage. Second District Rep. Jason Lewis spoke for several minutes as the president stood by. Lewis was followed by Jim Hagedorn, who's running in southern Minnesota's First District. Rochester is the district's largest city.

Trump aimed criticism at Democrat Dan Feehan, Hagedorn's opponent. "He wants to make Minnesota — true — a sanctuary for the criminal aliens."

Of Democrat Angie Craig, running against Lewis, the president said, "Who the hell is Angie Craig?"

"A vote for Dan Feehan and Angie Craig is a vote for Nancy Pelosi," Trump said, referring to the California Democrat in line to become House speaker if her party takes control of the House.

Trump also revisited a long-standing peeve: NFL players who kneel during the national anthem. A reference to Clinton, in which he said she wouldn't have called drug companies to ask for lower prices, prompted "lock her up" chants.

"We're standing up for your values, we're standing up for Minnesota and we are standing proudly for our national anthem," he said, setting off another long round of cheers.

Several protesters were hauled out by police as Trump spoke. Rochester officials said one person was arrested for a threat to the president and was also resisting arrest for trespassing. The Secret Service is investigating, the official said.

After waiting patiently for hours, the crowd erupted when Trump emerged just after 6:30 p.m. His backdrop was a giant U.S. flag flanked by signs reading "Promises Made" and "Promises Kept."

Citing improvements to the economy and his support for the Second Amendment, veterans and the military, Trump said that Democrats "want to take it all away. They want to destroy our prosperity."

Jeff Johnson, the Republican candidate for governor, went after his DFL opponent, U.S. Rep. Tim Walz. The loudest reaction came when Johnson said Walz would make Minnesota a sanctuary state "over my dead body."

Housley was greeted with roars when she said "the far left" must be prevented from impeaching Trump and denying Kavanaugh a Supreme Court seat.

Earlier in the afternoon, a large crowd of protesters marched through downtown Rochester holding Trump balloons and signs that read "I am greater than fear" and "Remember to vote."

The group stopped downtown, a block away from Trump supporters lined up outside the Civic Center, and chanted, "White, black or brown, all are welcome in our town." Rochester police estimated about 500 people were in the march.

Trump supporters were urged to not engage with the protesters. Recorded messages urged them not to touch protesters but to surround them and chant "Trump, Trump, Trump" until they could be removed.

"It's history" is how John Gordon, 60, described why he drove from Ellendale, Minn., for the rally. "I just want to hear what he's got to say."

Willa Dailey, chairwoman of the Blue Earth County Republican Party, said she was looking forward to hearing from a president who's exceeded her expectations.

"To have the opportunity to be right there with the leader of the free world, it's a big deal and it wouldn't matter who it was, it's a big deal," said Dailey, 62. "It just happens to be somebody I like very much.

Three local groups organized the rally and march to counter Trump.

"That's not who Minnesota is," said Regina Mustafa, 38, of Rochester's Community Interfaith Dialogue on Islam, one of the organizers. "We're greater than fear."

Alenna Bolin, 59, of Rochester took off work for her first political demonstration.

"I always thought that protests were for young people but I'm here," said Bolin, an attorney.

Outside, the crowd of Trump supporters broke out into a chant of "Kavanaugh, Kavanaugh, Kavanaugh!" Protester Garlyn Brentner, 27, of Rochester carried a neon green sign that read "Stand with Dr. Ford," a reference to Christine Blasey Ford, who has accused Kavanaugh of sexual assault while they were both high school students.

"Women need to be believed," said Brentner, who works in child care.

Before the stop in Rochester, Trump swung through the Twin Cities for a private Republican fundraiser for the party's congressional candidates. Trump last appeared in Minnesota at a June 20 Duluth rally.

Fairmont resident Cheryl Ortega, 43, got in line in Rochester at 5:15 a.m. "I just wanted to come and see the president. He fights for the people," she said.

Denis Post's daughter and grandchildren saved him a place in line so he could finish morning chores at his dairy farm in Mazeppa.

"He's our guy," Post, 62, said. "He's making good on his promises."

Staff writer Greg Stanley contributed to this report.

Judy Keen • 612-673-4234