The Guatemalan father carried his 6-year-old son on his shoulders as he walked with U.S. Border Patrol agents in the searing mid-morning sun after crossing California's border with Mexico.

They had been walking for two days in the scrubby mountains on the edge of Tijuana, Mexico. It is unforgiving cactus-dotted land. They came across agents about a mile away from the towering prototypes of the new wall that President Donald Trump has proposed building.

A Guatemalan father and son, who crossed the U.S.-Mexico border illegally, are escorted down a hill by a U.S. Border Patrol agent June 28, 2018, in San Diego. (AP Photo/Jae C. Hong)

The encounter illustrates the enduring arrival of migrants from Central America even in the face of the Trump administration’s zero-tolerance policy that at first separated thousands of immigrant children from their parents before it was halted under public pressure. A federal judge in San Diego has ordered authorities to reunite around 2,000 children who were separated from their parents when they were detained over the past month.

It was unclear if the father from Guatemala knew any of this. He quietly put his hands on his head as an agent patted him down. His son stood by watching, his face frozen. The agents allowed the man to take a water bottle from his backpack, after they checked its contents, and give his son a drink.

Then they were loaded into a waiting Border Patrol van already filled with a group of other immigrants from India caught earlier that morning.

A U.S. Border Patrol van drives up the hill to pick up migrants apprehended trying to cross the U.S.-Mexico border illegally as the Mexican land looks on the left side of the border wall along a road Thursday, June 28, 2018, in San Diego. (AP Photo/… — A U.S. Border Patrol van drives up the hill to pick up migrants apprehended trying to cross the U.S.-Mexico border illegally as the Mexican land looks on the left side of the border wall along a road Thursday, June 28, 2018, in San Diego. (AP Photo/Jae C. Hong)

On the other side of the border, there have also been daily signs about the flow of migrants into the U.S., many of them fleeing rampant gang violence in Central America.

About a dozen people swam across the Rio Grande near Brownsville, Texas in the early morning Friday, only their heads poking out of the water. A pedestrian bridge spanning over the river was lined with an equal number of asylum seekers _ from Cuba to Guatemala _ who reclined on towels and blankets on the steamy concrete on the Mexican side, waiting to hear from authorities as to when U.S. immigration officials can meet them to hear their cases.

Nicole Hernandez, of the Mexican state of Guerrero, holds on to her mother as they wait with other families to request political asylum in the United States, across the border in Tijuana, Mexico on June 13, 2018. The family has waited for about a we… — Nicole Hernandez, of the Mexican state of Guerrero, holds on to her mother as they wait with other families to request political asylum in the United States, across the border in Tijuana, Mexico on June 13, 2018. The family has waited for about a week in this Mexican border city, hoping for a chance to escape widespread violence in their home state. (AP Photo/Gregory Bull)

Immigrants from Guatemala and Cuba seeking asylum in the United States wait on the Matamoros International Bridge, Thursday, June 28, 2018, in Matamoros, Mexico. (AP Photo/Eric Gay)

A few days earlier, two Honduran women _ one with a 12-year-old daughter and one with a year-old boy _ turned themselves into Border Patrol agents after a smuggler carried them on a makeshift raft across the Rio Grande and dropped them off on its muddy banks as the temperature hovered close to 100 degrees near McAllen, Texas.

Agents the same day found Gerberht Charac, 19, and a fellow Guatemalan man on the roof of a trailer after they swam across the Rio Grande. Charac said he agreed to pay a smuggler $12,000 to get from Guatemala to Houston, where he planned to join a friend.

"I had hopes of making it," Charac said, choking up as he explained that he just wanted to provide for his wife and daughter in Guatemala.