Joel Rose

The Social Security Administration may be the latest front in the Trump administration's crackdown on illegal immigration.

The agency is reviving the controversial practice of sending "no match" letters to businesses across the country, notifying them when an employee's Social Security number doesn't match up with official records.

That may sound innocuous. But these no-match letters are expected to set off alarm bells. That's what happened when they arrived in the mail back in the mid-2000s.

Updated at 6:45 p.m. ET

Immigration authorities are expressing alarm about the growing number of migrants crossing the Southern border.

Federal agents apprehended more than 4,000 migrants crossing the border on each of two days this week — the highest daily total recorded in 15 years, according to a senior official with Customs and Border Protection.

Irsi Castillo clutches her 3-year-old daughter to her chest to shield her from the wind. They've just crossed the Rio Grande and stepped onto U.S. soil in El Paso, Texas, after traveling from Honduras.

Thousands of migrants like Castillo are crossing the border every day and turning themselves in to the Border Patrol. They're fleeing poverty and violence in Central America.

The Trump administration is expanding a hard-line immigration policy that forces asylum-seekers to wait in Mexico for their assigned court dates in the U.S.

The U.S. Border Patrol apprehended more than 66,000 migrants at the Southern border in February, the highest total for a single month in almost a decade.

For years, volunteers have left food and water in remote stretches of desert along the U.S.-Mexico border. They say they're trying to save the lives of migrants making the dangerous crossing. But the government argues these volunteers are encouraging illegal immigration.

Now several volunteers face jail time when they're sentenced on Friday.

"What we've seen in the last two years is a real escalation," said Catherine Gaffney, a spokeswoman for the activist group No More Deaths.

During the 2016 presidential campaign, Fatima Farheen Mirza's family received an unexpected gift.

At least, that's how it seemed when a neighbor's daughter delivered a bag of candy to their front door. Mirza's parents had recently moved to Texas. At first, Mirza's mother thought the candy might be a sort of welcome to the neighborhood.

"Then Mumma looked closer," Mirza writes.

It wasn't a gift bag, but a Ziploc plastic bag — "unadorned and filled only with Skittles."

In a desolate stretch of desert outside Yuma, Ariz., there's a spot where more than 350 migrants, including children, burrowed under the steel border fence a few weeks ago.

"This only goes down just about probably another foot, this steel," said Anthony Porvaznik, chief patrol agent for the Yuma sector of the Border Patrol. He says smugglers tried digging in more than a dozen spots, looking for places where the ground was soft enough.

"This is very sandy," Porvaznik said. "It's like that all the way down, and so it was easy to dig."

When the young woman from Nicaragua got off the plane in South Florida, she hadn't seen her parents since they left their tiny Central American town to find work in the U.S. more than a decade ago.

"When I saw them, I ran to hug them," she said through an interpreter, her eyes lighting up as she described their reunion at the airport.

"I felt a huge joy when I saw them again, and I knew that I was going to be here, protected," she said.

President Trump used his first prime-time address from the Oval Office to make the case for his controversial border wall. The president's demand for $5.7 billion in wall funding — and Democrats' opposition — has led to a partial shutdown of the federal government.

Here we check some of the arguments made by the president and top Democrats in their response.

Trump's Speech

Claim 1: Humanitarian and security crisis

"There is a growing humanitarian and security crisis at our Southern border."

Updated 3:55 pm E.T. Friday

The government shutdown began with the president's demand for border security money. But it has also halted E-Verify, a federal program that's supposed to prevent immigrants from working here illegally.

If U.S. employers want to check whether their prospective hires are eligible to work, they can't. The E-Verify database is "currently unavailable due to a lapse in government appropriations," according to a note on the government-run website.