A drone view shows asylum seeking migrants from China and Turkey as they climb a hill while looking to surrender to immigration officials after crossing the border into the United States from Mexico in Jacumba Hot Springs, California on May.20. / Reuters/Adrees Latif

JACUMBA HOT SPRINGS, California (Reuters) - Propped up against the rusty steel slats of the border wall, migrant families who hours before crossed the US-Mexico border rest under tarps and tents and await Border Patrol officers.

Some of the families along this remote desert stretch in San Diego County have brought their children with them, including small infants.

In recent months, the San Diego-Mexico border has become one of the busiest crossings for migrants seeking safe haven and opportunities in the United States.

In May, Reuters reporters came across Colombians, Ecuadoreans, Peruvians, Turks, Brazilians, Jordanians, Egyptians, Indians and Chinese - a more varied mix than the Mexicans and Central Americans who formed the bulk of migrants in years past.

The high volume of crossings has ignited a political firestorm for President Joe Biden as the Democrat seeks re-election in November. And they have provided Republicans and their likely presidential candidate Donald Trump with plenty of ammunition to criticize Biden's immigration policy.

The Biden administration is hoping the number of migrants crossing will drop following the announcement this week of a broad asylum ban that would deny migrants caught crossing illegally the right to claim asylum.

The Biden administration said high rates of border arrests has triggered the measures, which took effect immediately but include exceptions for unaccompanied children, people who face serious medical or safety threats and victims of trafficking.

In April, close to 30 percent of all the Border Patrol arrests across the US-Mexico border were in the San Diego sector, US Customs and Border Protection data showed. So far this fiscal year, which began in October, there have been more than 1.16 million migrant apprehensions border-wide.

The many Colombians here say their country has become too dangerous and they have received threats against their lives.

"There were threats towards me," said Edward, a 35-year-old teacher who asked that only his first name be used.

"Where we lived, there was lots of insecurity. And sadly, from February, they started threatening us and we decided to come here," he added.

He came with wife Luisa and their 11-month-old daughter and they hope they can make their way to New York.

"Yes, we were worried" about traveling with such a small child," said Edward. "But we were also thinking about the situation we were in."

Down the fence, groups of migrants travel to a hilly, boulder-covered area where there is a break in the border fence. They clamber around the fence and then head off to areas where they will be picked up by Border Patrol.

Kali Kai Braun, a 49-year-old property manager at a gun range that sits just inside the US border, said large groups have started to come over in the middle of the night. He witnessed recently a group of 70 to 100 migrants crossing at 1 a.m. and stayed up to make sure they didn't go onto the property. He usually sees an average of 30 to 40 migrants a day, mostly crossing in the morning.

"It is truly insane what I have seen in the last year," Braun.

WAITING IN HEAT AND SUN

Most migrants walk to open-air sites, and in the afternoon, they are lined up and a Border Patrol agent takes pictures of their documents and faces and loads them into buses to take them to a processing center.

Local resident Karen Parker, 61, brings water, snacks and medical supplies to waiting migrants. She was spurred to help them when a migrant woman was shouting in front of her house a year ago because she had lost her children.

"So I went looking for her kids and I found 1,000 people from all over the world," said Parker. "She found her kids. It's a small town."

Parker said last winter and summer, migrants would be waiting by the border fence for longer periods of time.

Jacumba Hot Springs in southeastern San Diego has long been a place of migrant arrivals, but residents witness what Parker calls "hundreds of traumatized people every day."

"I would like to see our government, the Border Patrol take some responsibility and improve the conditions in this camp, the safety of the children and the families that are here in this area," said Parker.

And she would like to see the transport operations pick up the children faster, so they don't have to wait in the heat and sun, without shelter and shade.

A federal judge on Apr.3 ordered US border agents to “expeditiously process” any children out of "open air" detention sites. The ruling came in the long-running, court-mandated agreement on the treatment of migrant children in federal custody, known as the Flores settlement.

US Customs and Border Protection did not respond to a request for comment.

ECONOMIC OPPORTUNITY BECKONS

Three men from Jordan said they flew in through Nicaragua, now a hub for migrants heading towards the United States.

They said it was hard to make ends meet in Jordan and they couldn't get married because they didn't make enough money. The trip from Nicaragua was hard and they were robbed in Honduras.

One of the men, who said his first name was Moath, graduated in 2017 and wanted to work in physical education. He could not find a job.

"My dream and my life, I want to come to America," said Moath, 33, who plans to head to Florida while his two fellow Jordanians are going to Chicago.

On some days, no migrants come over. Reuters observed how the Mexican military stopped migrants from crossing by setting up a patrol on their side of the fence.

US Senator Chris Murphy, the lead Democrat who negotiated a bipartisan border security bill that failed to pass in Congress, said a recent decrease in the number of border crossings was due to "smart, effective diplomacy between the United States and the Mexican government."

Biden implemented the new asylum policy after Trump pushed Republicans to vote against the legislative deal.

Alejandro, a 50-year-old Colombian who had to flee after his father was killed and who is afraid to give his full name, hopes the American people will understand their plight.

"Those of us here in this foreign land we are equally human beings ... we feel pain and happiness. We hope we are received with warm human qualities and that we are treated like human beings," and then he added "God made us all."