WASHINGTON -- Republican Donald Trump told a motorcycle rally on Sunday that illegal aliens receive better care than the nation's veterans, electrifying the crowd at the annual Rolling Thunder tribute to the armed forces.

"Thousands of people are dying waiting in line to see a doctor. That is not going to happen anymore," Trump told veterans gathered in front of the Lincoln Memorial.

The Rolling Thunder event, which draws thousands of motorcyclists to Washington each Memorial Day weekend, is organized to focus attention on veterans issues and is dedicated to remembering prisoners of war and service members missing in action.

Trump promised that he would improve health care for veterans and rebuild the military.

"When you think of the great Gen. [George S.] Patton and all our generals, they are spinning in their graves when they watch we can't beat ISIS," Trump said, using an acronym for the Islamic State militant group. "We are going to knock the hell out of them."

The line drew some of the loudest applause of the day from the crowd, many of whom wore Trump stickers and shirts and waved his campaign signs. There were no signs of anti-Trump protesters or skirmishes. Police reported no arrests at the event.

Rolling Thunder spokesman Nancy Regg estimated that Sunday's event drew about 5,000 people. Trump, however, said 600,000 people were trying to get in.

"I thought this would be like Dr. Martin Luther King, where the people would be lined up from here all the way to the Washington Monument, right? Unfortunately, they don't allow 'em to come in," Trump said.

Regg said Rolling Thunder invited Trump to speak but did not extend an invitation to former Secretary of State Hillary Clinton or to U.S. Sen. Bernie Sanders of Vermont.

Richard McFadden, 58, of North Carolina, who annually attends the Rolling Thunder event, said Clinton would not have been welcome.

"Just like asking Jane Fonda to show up, it'd be a very, very bad thing," McFadden said. Fonda was dubbed "Hanoi Jane" after visiting the North Vietnamese capital in 1972, where she made radio broadcasts critical of U.S. policy and sat on an anti-aircraft gun.

John Such, a 55-year-old Navy veteran from Ohio, said Trump's message that the U.S. needed to project power in the world contrasted with President Barack Obama's Friday appearance in Hiroshima, Japan, where he greeted survivors of America's atomic bomb there in 1945.

"[Trump] stands for what I stand for: making America strong," Such said. "We've lost too much in the last eight years."

Challenge by Sanders

Sanders, campaigning in California for the Democratic presidential nomination, disputed the notion that Trump was a strong leader.

"I say to Donald Trump -- you're a big, macho guy," Sanders said Saturday night at a rally in Bakersfield, Calif. "If you have any guts, come on down and let's debate."

Sanders has been trying to pressure Trump into a debate to draw a contrast with Clinton, the Democratic front-runner, who has refused to debate Sanders before the next round of primaries on June 7. At one point last week, Trump indicated that he was interested, but then he backed off.

California is the biggest prize in the June 7 primaries. Sanders on Sunday called it the "big enchilada" in his attempt to overtake Clinton and claim the Democratic presidential nomination.

"What I want to do, and I think we can, is win California here, and win under the big vote, do very, very well in the other five states," Sanders said on NBC's Meet the Press.

But, he said, his campaign will not end if he loses in California.

"Obviously if we don't do well in California, it will make our path much harder. No question about it," he said.

Sanders said Trump "would be a disaster as president" and pledged to "do everything that I can to make sure that does not happen."

Trump faces challenges beyond Sanders in his bid for the presidency. U.S. District Judge Gonzalo Curiel in San Diego is ordering the release of Trump University internal documents this week in a class-action lawsuit against Trump's now-defunct real estate school.

The lawsuit, being overseen by Curiel, states that Trump University's nationwide seminars and classes pressured students to buy more but didn't deliver as promised in spite of students paying as much as $35,000 for seminars. Curiel has set a Nov. 28 trial date.

Trump's lawyers deny any wrongdoing in the case before Curiel as well as in another class-action suit in San Diego and a $40 million lawsuit filed in 2013 by the state of New York alleging that more than 5,000 people had been defrauded.

Trump has questioned whether Curiel, who is Hispanic, is biased against him because of his call for deporting migrants in the U.S. illegally, though he has also said that "the Mexican people" will vote for him "like crazy."

On Sunday, Trump reiterated his call to build a wall along the Mexican border. When he asked the crowd in Washington who was going to pay for it, a chorus rang out: "Mexico!"

Looking at Florida

The Hispanic population represents a key demographic in Florida, where Obama defeated Republican Mitt Romney four years ago by fewer than 75,000 votes out of more than 8.4 million cast.

One of Trump's vanquished primary rivals, Sen. Marco Rubio, R-Fla., told reporters last week that Trump can win Florida as long as he can "continue to be Donald."

But experts say Trump must expand his reach.

"If he can't unify Republicans, there really isn't enough votes for him to make up elsewhere," said Steve Schale, who ran Obama's 2008 campaign in Florida.

"We still elect presidents using the Electoral College ... depending on states that are made up of diverse electorates," added GOP pollster Whit Ayres. "There aren't enough angry white people to create a majority in the new America of 2016. Running up your numbers with white males in Mississippi doesn't get you one more electoral vote than Mitt Romney."

Some Floridians mocked Trump's claims about his own appeal.

"I haven't heard any of my [black] friends say they'll vote for Trump," said Tanisha Winns, 39, a black Democrat in Lakeland, located along central Florida's Interstate 4 corridor. The city twice helped give Republican George W. Bush the statewide victory before swinging in Obama's favor. "If anything, I'm hearing my white friends say they won't," Winns added.

In Clearwater, Republican Barbie Sugas said she's always voted for the GOP nominee, but the 47-year-old surgical technician said she's "kind of leaning toward Clinton" because she doesn't "trust Trump" with international affairs.

Others are concerned about Trump's history with the military. The candidate avoided the draft through four student deferments and was later medically disqualified from service. He also angered some veterans last year when he said he liked "people who weren't captured" in wars. That had been a dig at Sen. John McCain, R-Ariz., the party's 2008 nominee, who had been captured and held for more than five years during the Vietnam War.

Trump later said that he never questioned whether McCain was a war hero, but he declined to apologize outright.

More recently, Trump has had to answer questions about why he had not fulfilled a pledge to transfer $6 million to veterans causes after a nationally televised fundraiser in January. Trump said during his speech Sunday that he planned to hold a news conference on Tuesday to name the charities to which he had given the proceeds from the fundraiser.

Veteran Art Bleich, 63, who served with the Marines in Vietnam, has made the ride from his home in Alabama to Washington, D.C., to attend Rolling Thunder for about 15 years. He said he would likely support Trump, though he was uneasy about the candidate's lack of military service.

"What he said about McCain was not right," Bleich said. "He has a right to his opinion, but he didn't play the game, so he really doesn't have a right to speak."

But veteran Mike Sukeena said Trump was right to criticize McCain.

"McCain was a prisoner of war, but I don't know -- I think he's deserted the veterans, I really do," said Sukeena, 72, who served in Vietnam during his six years in the Navy. "All of them have turned their back on the veterans."

Sukeena said he plans to vote for Trump.

"I like the fact that he's going to make America great again and that he's going to work for our veterans," he said.

Also attending Rolling Thunder were two retirees from New Jersey, Tom Gadosky and his companion, Marney Pratt, both 67. Both plan to vote for Trump in November.

"A lot of the people, if you walk around, are baby boomers like us," Pratt said. "We've been through it all. We want to have it back again."

Information for this article was contributed by Bill Barrow, Sergio Bustos, Jonathan Lemire, Jill Colvin of The Associated Press; by Justin Jouvenal and Jose A. DelReal of The Washington Post; by Thomas Kaplan of The New York Times; and by David Savage and Cathleen Decker of the Los Angeles Times.

A Section on 05/30/2016