JUDY WOODRUFF: For about two weeks, thousands of migrants, refugees, and asylum seekers
fleeing Central America have joined a now well-known caravan making its way through
Mexico toward the U.S. border.
It's become a focus of President Trump, as he seeks to restrict the caravan's progress.
Many of these travelers are escaping violence and poverty.
And as foreign affairs correspondent Nick Schifrin reports, their journeys are long
and difficult.
NICK SCHIFRIN: Every night, they come together, feeling safer in a large group, searching
for some sleep.
This is the central square of Mapastepec, 70 miles north of the Mexico-Guatemala border.
Their shoes are worn from the walk.
Many have already been on the road for 500 miles.
They have picked up friends along the way, and take a quiet moment to themselves; 23-year-old
Karla Cruz might keep in touch with her boyfriend back home in Honduras, but her hopes are northward,
in the U.S.
She's brought only what she can carry, and fills a bag that was her blanket.
She jokes about her DIY bedding to beat the loneliness.
They set off at 3:00 a.m. to beat the heat.
Cruz knows these towns well.
This is her fourth attempt to get to the U.S. She was detained on the U.S. border once and
didn't even make it the other three times.
But she says this time feels different.
KARLA CRUZ, Migrant (through translator): Around the bend, there could be criminals
waiting for you.
You have to go around them.
You have to go around immigration.
But here, we're going in a legal way.
They are opening the doors to us, and no one is stopping us.
We're going in unison, together.
NICK SCHIFRIN: During the day, she rests in temporary shelters, where infants wear their
American icons and dreams around their necks.
Cruz's dream is reunification.
Fifteen years ago, her mother moved to Texas, leaving Cruz behind when she was just 8 years
old.
KARLA CRUZ (through translator): You don't have the words to say it because you're also
so young.
So it's terrible, how parents abandon their children for a better future?
The truth is, I will be content with just seeing my mom, even if it means I will get
deported.
Well, after 15 years, don't you think I do deserve a smile?
NICK SCHIFRIN: The caravan began in Honduras two weeks ago and quickly grew to 7,000.
It shrunk to 4,000 after many chose to board buses that returned them home.
And while most of the migrants talk about hopes, their critics talk about threats.
DONALD TRUMP, President of the United States: And in that caravan, you have some very bad
people.
You have some very bad people.
And we can't let that happen to our country.
We need a wall built fast.
NICK SCHIFRIN: Today in Calexico, California, workers finished a new section of that wall
inaugurated by Secretary of Homeland Security Kirstjen Nielsen.
The administration is considering additional legal steps to block the caravan's progress
and announced it will send 800 additional troops to the border in a support role.
KIRSTJEN NIELSEN, U.S. Secretary of Homeland Security: We do not have any intention right
now to shoot at people.
They will be apprehended, however.
But I also take my officer and agent, their own personal safety, extraordinarily seriously.
They do have the ability, of course, to defend themselves.
NICK SCHIFRIN: For Raul Marquez says no U.S. policy will prevent him from walking north.
He carries only what fits in his backpack and his hands.
His son is 1-year-old.
Marquez says he lived in the U.S. until about eight years ago, when he was deported after
two DUIs.
He says he was trying to rebuild his life in Guatemala, until gangs killed his wife.
RAUL MARQUEZ, Migrant: They told me that if I wasn't going to cooperate with them that
my son was going to be next, that he was -- they were going to cut his head off.
So, right when this was going on, that's when I heard about this caravan.
NICK SCHIFRIN: Guatemala and its neighbors are the most violent places on Earth outside
of war zones.
The migrants know the U.S. doesn't accept economic asylum cases, and so they admit they
might have to try and cross illegally in smaller groups.
Still, they have a message for President Trump.
KARLA CRUZ (through translator): I want to go see my mom.
I want to get ahead.
I want to maybe finish university.
I want to maybe learn his language, and that he also understands that we're not criminals.
We're people who want to better ourselves.
NICK SCHIFRIN: They still face a long journey that is physically and politically treacherous.
But they say they take strength from their numbers and their hopes.
For the "PBS NewsHour," I'm Nick Schifrin.