HOUSTON -- Donald Trump, who has made a hard-line stance on immigration a centerpiece of his presidential campaign, asserted Saturday that "not one more American life should be given up in the name of open borders."

Trump spoke Saturday to members of the Remembrance Project, a group founded to remember those killed by people living illegally in the U.S. and to press for tougher laws.

Also Saturday, in Washington, President Barack Obama was to deliver his final keynote address to the Congressional Black Caucus Foundation, while the person he hopes will succeed him, Hillary Clinton, will be honored for becoming the first female presidential nominee of a major party.

Trump told the Remembrance Project that "all across this country, dining room tables have an empty seat because the government abandoned its duty and has not enforced its basic laws. This has to end. This will end if I become president."

Two dozen members of the organization sat behind Trump as he spoke, and several told their stories, often graphic, of how their loved ones lost their lives. Trump has appeared with members of the group several times, including during the speech to lay out his immigration policy in Arizona last month. He vowed to continue to "shine a national spotlight" on their work.

"Politicians ignore your cries, but I never will," Trump said.

Maria Espinoza, founder of the group and daughter of a Mexican immigrant, praised Trump's advocacy. But the Houston-based group has come under scrutiny for some of its pronouncements, including Espinoza's assertion that immigrants who are in the U.S. illegally kill 25 Americans a day.

Trump has long talked tough on immigration, deriding Mexico as a source of rapists and criminals in his campaign kickoff speech last year and vowing to build an impenetrable wall on the nation's southern border.

He is not proposing a pathway to legal status for people living in the U.S. illegally but has backed away from his call for the mass deportation of millions of people who have not committed crimes beyond their immigration offenses. He also ruled out what he dismissed as "amnesty," saying those who want to live legally in the U.S. will need to leave and head to the back of the line in their home countries to apply to return.

The Republican nominee drew criticism late Friday after he said the bodyguards assigned to Clinton should "disarm immediately" and "see what happens."

"She goes around with armed bodyguards like you have never seen before. I think that her bodyguards should drop all weapons. They should disarm. Right? Right?" Trump said during a campaign rally in Miami as the crowd cheered the idea. "I think they should disarm immediately. What do you think? Yes? Yes. Yeah. Take their guns away. She doesn't want guns. ... Let's see what happens to her. Take their guns away, OK? It would be very dangerous."

Trump's comment came as he described the violence in inner-city neighborhoods as "far more dangerous than Afghanistan." Trump said "Clinton lives behind gates and walls and guards" and that working-class families "just want a fraction of the security enjoyed by our politicians and certainly enjoyed by her."

In a statement, Clinton campaign manager Robby Mook said, "Donald Trump has a pattern of inciting people to violence. Whether this is done to provoke protesters at a rally or casually or even as a joke, it is an unacceptable quality in anyone seeking the job of commander in chief."

Trump made a similar comment in May when he addressed a National Rifle Association conference.

Trump tweeted May 21: "Crooked Hillary wants to get rid of all guns and yet she is surrounded by bodyguards who are fully armed. No more guns to protect Hillary!"

While Trump campaigned in Texas on Saturday, his running mate released a two-page letter from his doctor vouching for his "excellent" health, summarizing his medical history and results of a July physical exam.

Indiana Gov. Mike Pence, 57, released the letter after Trump, Clinton and her running mate, Tim Kaine, provided some details of their medical histories. The health of the candidates has become more of an issue in the campaign since Clinton stumbled at a 9/11 memorial event last week and revealed afterward that she had been diagnosed with pneumonia.

Pence's doctor, Michael Busk, disclosed that Pence had basal cell carcinomas -- skin cancer -- removed from his face in 2002 and 2010. He also had surgery in August 2015 to repair a hernia. The doctor said the only medication Pence takes is Claritin for seasonal allergies, he does not smoke or drink alcohol, has diet-controlled heartburn and exercises four times a week.

Pence also has a condition known as "left bundle branch block," which causes the heart's left ventricle to contract later than the right ventricle. Pence had "extensive evaluations" at the hospital in 2014 after the discovery of that condition, and Busk wrote "the cardiologists feel you have a very good and strong heart."

Busk is a doctor with the St. Vincent Health, Wellness and Preventive Care Institute in Indianapolis.

Later Saturday, Trump was to attend a fundraiser in Oklahoma, though arrangements were not made for reporters who travel with Trump from city to city to follow him there. Trump also planned a rally in the battleground state of Colorado on Saturday night.

Sanders talks up Clinton

On the Democratic side, U.S. Sen. Bernie Sanders of Vermont spent Saturday visiting two universities in battleground Ohio, banking his primary-campaign popularity with young voters to urge support for Clinton.

Sanders praised his former rival's agenda as the right choice for millennial and union voters, and said those who are turned off by their choices in the election should still turn out, even if they think "everybody's horrible."

Sanders told gatherings at the University of Akron and Kent State that Trump's statements against Muslims, women, Mexicans and other groups threaten to unravel decades of work to improve equality.

"We can't in 2016 accept bigotry as the cornerstone of any campaign," he said.

Sanders also promoted Clinton's positions on climate change, a minimum wage increase and tuition-free public college.

"When you talk to your friends and they say, 'I'm not going to vote, everybody's horrible,' ask them how much they're going to leave school in debt," Sanders said. "Ask them about that."

About 200 attended his Akron rally; about 600 showed up at Kent State. It was a far cry from the throngs overflowing his events during his heated contest with Clinton in the primary season. Even so, Sanders struck home with some as he asked people to swing behind Clinton.

"Before today, I was not persuaded one bit, but I think Bernie made a pretty convincing case," said Dallas Tucholski, a 20-year-old University of Akron senior wearing a T-shirt plastered with Sanders faces. "I trust Bernie; I think he's the one good, honest politician that's left out there. For him to stay out on the trail -- he doesn't need to do this -- you can tell he cares about us and cares about the future. So I'm going to take his advice and vote for Hillary Clinton."

But many rally attendees remained undecided.

Sam Woofter, 18, a computer engineering major at the University of Akron, said he's having a difficult time picking an alternative to Sanders.

"I voted for him in the primaries and yelled at my friends for not voting for him in the primaries," he said. All he can tell his friends now is, "You should have voted in the primaries."

Shaheeda Haque, 17, said many friends at Akron University plan to stay home on Election Day. They dislike Trump and believe Clinton's "terrible, or a snake or whatever."

"I definitely think that Hillary needs Bernie to get up there and endorse her, because he just has so much millennial support behind him," she said. "So I think it's pretty important for us to feel secure, for us to hear from this man that we trust that we can trust Hillary Clinton."

Information for this article was contributed by Jonathan Lemire, Scott Bauer, Julie Carr Smyth and staff members of The Associated Press; and by Sean Sullivan and Jenna Johnson of The Washington Post;

A Section on 09/18/2016