REYNOSA, Mexico – Over the past year, Lilian Menendez has evaded street gangs in her native Honduras, paid $5,000 to free her kidnapped brother and made the perilous 2,000-mile journey from her home country to this border city.

Now, Menendez and husband, Osman Guillen, face perhaps their most daunting task: Turning themselves into U.S. authorities to seek asylum.

Rebuffed at the international bridge that leads to McAllen, Texas – and to U.S. sanctuary – Menendez said she was calling relatives to scrape together the $10,000 smugglers are demanding to float them across the Rio Grande, where they can turn themselves into Border Patrol agents and begin applying for asylum.

“I’m at the point of desperation,” said Menendez, who has been staying at a migrant shelter near the border since Jan. 1. “The idea was to cross the bridge and ask for asylum. But they tell us we can’t.”

Under international law, migrants have for years flocked to the U.S.-Mexico border to legally seek asylum and be allowed entry. But in recent months, Trump administration policies have slowed the flow of asylum-seekers into the U.S., leaving many migrants stranded far from home, vulnerable to violence in dangerous border cities and unable to request asylum.

Determined to find a way in, migrants like Menendez are increasingly turning to criminal smuggling rings to get to the U.S., where they can then request asylum and, the hope is, seek safety. The backlog in processing asylum seekers is inadvertently bolstering the illicit and dangerous trade, according to migrants, advocates and experts, creating an increased demand for human smuggling and illegal border crossings at a time when President Donald Trump has threatened to once again shutdown the government in February if his proposed border wall isn't built.

Starting last summer, U.S. Border and Customs Protection initiated a program known as “metering," where only a limited number of asylum-seekers are allowed through legal ports of entry each day, creating a backlog of migrants on the Mexican side of the border.

The White House began implementing a new policy Tuesday where certain migrants given a U.S. immigration hearing will be removed to Mexico to await their day in court. Current U.S. law allows some migrants to stay in the U.S. until their court date arrives.

The Pentagon on Sunday also announced it will be sending 3,750 more troops to the U.S.-Mexico border to help lay down concertina wire and support Border Patrol units, brining the total number of active-duty troops on the border to 4,350. Migrant advocates and analysts say the steady military build-up at the border also make asylum-seekers seek out illegal smugglers to guide them across more remote areas of the border.

In the Rio Grande Valley, independent smugglers are charging exorbitant prices to sneak desperate migrants across the river and into the U.S., said Guadalupe Correa-Cabrera, a political scientist at George Mason University in Virginia and author of "Los Zetas Inc.," about the deadly Mexican criminal group known for their migrant-smuggling and extortion activities that recently splintered into different cells. The smugglers then pay fees to larger criminal gangs, such as remnants of Los Zetas and the Gulf Cartel, she said.

"From Central American smugglers, to independent smugglers along the border, all the way up to the cartels: Everyone’s making money," she said.

Smugglers are also increasingly shifting routes to New Mexico and Arizona, where migrants and advocacy groups can more easily help deliver migrants to U.S. authorities, Correa-Cabrera said. But the border terrain there is also more hostile, with vast deserts and mountains and farther away from major cities, she said.

"You're starting to see more families trying to make it through more dangerous areas," Correa-Cabrera said. "The smuggling business is going to change dramatically."

The Department of Homeland Security, which oversees border security, insists it is not turning away asylum-seekers. Officials say the metering process is in place to prevent ports of entry facilities from overflowing.

The Trump administration is also facing an unprecedented rise in asylum requests. The total number of credible-fear referrals for interviews -- or migrants seeking asylum -- skyrocketed from about 5,000 a year in fiscal year 2008 to about 97,000 in 2018. At the same time, the number of total apprehensions along the Southwest border dropped in the same period, from 705,005 in 2008 to 396,579 last fiscal year, according to Homeland Security and Border Patrol statistics.

"The bottom line is that we have a deeply flawed immigration system, smugglers and traffickers know the flaws well, and they seek to exploit these vulnerabilities in the law, as well as physical vulnerabilities to enter and remain in the country illegally,” DHS spokeswoman Katie Waldman said.

Border officials are aware of the smuggling problem. A September report from DHS's Office of Inspector General found that "while the government encouraged all asylum seekers to come to ports of entry to make their asylum claims, CBP managed the flow of people who could enter at those ports of entry through metering, which may have led to additional illegal border crossings."

Investigators interviewed one woman who said she was turned away three times by a border agent before deciding to take her chances with illegal entry, according to the report. Two other migrants told them they crossed over illegally after being turned away at the bridge.

A Border Patrol supervisor told the investigation team the sector sees an increase in illegal entries when migrants are metered at ports of entry. "While the stated intentions behind metering may be reasonable, the practice may have unintended consequences," the report said.

At the Senda de Vida migrant shelter in Reynosa, a large steel gate protects the front entrance, keeping out criminal gangs that prey on the migrants gathered there. Inside, asylum-seekers, mostly from Guatemala and Honduras, rest in bunk beds or gather in small groups to plot ways to reach U.S. officials and plead their case for asylum.

Very few migrants are being allowed to cross over the nearby McAllen-Hidalgo International Bridge, said Hector Silva, the pastor who runs the shelter. Those turned away from the bridge -- either by border patrol agents or Mexican immigration officials -- are susceptible to criminal gangs that roam the area, he said.

The gangs have kidnapped migrants and held them for thousands of dollars in ransom, beat them up or swindled them out of money, Silva said. Instead of exposing themselves to those gangs, some migrants are looking into illegal crossings, he said.

"The entrance they had hoped for doesn't present itself, so they risk other ways in: over the river, over mountains, with smugglers," Silva said. "It becomes very difficult for them."

On a recent day, Melendez and Gullien sat on a concrete curb inside the sprawling shelter, checking his cell phone for news from relatives. Street gangs in their hometown, La Libertad, Honduras, made them pay a weekly "war tax" on their deli, then threatened to kill Guillen, so they left.

They left behind two daughters, 9 and 17 years old, because of the journey's dangers. They had hoped to join relatives in Round Rock, Texas, then send for their girls. They didn't expect to be held up at the border.

Maria Alfaro, 51, of San Pedro Sula, Honduras, arrived at the migrant center in November. She said she's afraid to try to cross over the international bridge because she's heard of the backlog and doesn't want to be turned away and snatched by cartels.

She was kidnapped in Chiapas, Mexico, during her journey to the U.S.-Mexico border last year, a harrowing ordeal she said she doesn't want to go through again. She escaped after a shootout broke out between her captors and Mexican authorities, she said. Afterwards, she headed toward Reynosa for U.S. protection.

"I came here to seek asylum," Alfaro said. "But there's no where to go."

Migrants waiting for asylum across the U.S.-Mexican border expressed similar fears and complaints about their state of limbo. For many, waiting in line to request in asylum didn't seem like the wisest long-term strategy.

Sixty miles to the southeast, in Matamoros, Mexico, just across the bridge from Brownsville, Texas, migrants have set up a makeshift camp of sleeping bags, backpacks, strollers and heavy jackets under the international bridge connecting the two countries. The migrants, mostly from Central America, are not allowed to sleep there overnight.

Marlin Martinez has showed up to the camp every day for the past three weeks with her three children, ages 9 to 12, hoping to apply for asylum in the U.S. Each day, Mexican immigration officials have told her to come back the next day, she said.

Martinez, who was fleeing a violent ex-partner and street gangs in Honduras, said she will hire a smuggler to get them across, as soon as she raises enough money to pay them.

"We didn't come here to violate any laws," she said. "We came to seek asylum. It's in God's hands now."

To be sure, Trump's policies have persuaded some migrants to patiently wait their turn at the border.

In Nogales, Mexico, migrants showing up to claim asylum are waiting up to three weeks to talk to U.S. immigration officials. Community groups created a numbering system to house migrants in shelters around the city and transport them to the crossing when they're number is close to being called.

At a migrant shelter known as La Roca, or the Rock, several migrants said that given the option between waiting in line to talk to an immigration officer or hiring a smuggler to get across the border, they’d rather wait, despite restrictions from the U.S. government.

The reason, they said, is the costs. As it becomes tougher to get across the border, smuggling prices have gone up, to the point that many of them say they just can’t afford it.

“The (smugglers) I looked into were charging $7,500 each… adults or kids, you have to pay the same amount,” Efrain Javier Gonzalez said. He arrived in Nogales last week with his wife and two kids, ages 11 and one. They fled cartel violence and extortion from Guerrero state, a notoriously dangerous part of Mexico.

They’re the only Mexican family staying at La Roca. The shelter sits atop a steep hillside directly facing the rusty, bollard-style border fence that separates them from the United States. It’s so close, that Gonzalez' sons regularly wave to the Border Patrol agents driving just behind the metal slats.

Gonzalez previously lived in New Jersey before he agreed to a voluntary deportation in 2016. He hired a smuggler in 2009, borrowing money and selling belongings to pay the $4,500 fee at the time for the four-day walk across the desert.

But it’s a different story now. It’s risky, he said, and the family sold all their belongings to leave Guerrero, so they have no money left for a smuggler, and certainly not the $30,000 he’d have to pay to get the entire family across.

“Here at the border, there are smugglers everywhere. They offer their services, but you know it’s just not 100 percent reliable,” he said. “You make that decision without the certainty that they will follow through. There are smugglers who will get you across, but there are also those who will only take your money and leave you to your luck.”

Other migrants at La Roca in Nogales who are not seeking asylum in the U.S. said they would also rather try their luck on their own, rather than hire smugglers.

“You need a lot of money,” Luciano Morales, a Mexican migrant from Sinaloa, said as he packed all his belongings into a backpack and a gym bag. He would soon head out to Tijuana where he would attempt to cross the border on his own.

“It’s just a matter of staying close to the lights so I don’t get lost in the desert," he said.

But there's no question that more and more migrants are choosing smugglers to help them reach vulnerable areas along the border that can be used as illegal entry points, said Jose Garibay, spokesman for Border Patrol’s Yuma Sector. More than 8 out of 10 migrants border agents apprehend here are migrant families or unaccompanied minors, enforcement statistics show. In the past year they’ve increasingly been crossing in larger groups, and willingly turned themselves in to agents.

As evidence, Garibay pointed to two videos taken six days apart in the Yuma border area. They show dozens of migrants scaling the border fence using ladders. At the end of the clips, the presumed smugglers are caught on camera running away with the ladder in hand.

“They can just theoretically point at a section of wall or, as in this case, give them a ladder or a system over the border wall,” Garibay said. “They don’t have to cross with them, they can just stay in Mexico where they know we can’t go.”

Migrant advocates say they fear stricter restrictions on asylum claims or the prospect of waiting out court dates in Mexico will lead more families to pursue dangerous and illegal border crossings.

"We can see families now wandering for days in the desert, and we’re afraid that that humanitarian cost will be high,” said Joanna Williams, advocacy director for the Kino Border Initiative, a faith-based aid group for deported migrants and asylum seekers in Nogales, Mexico.

Follow Jervis on Twitter: @MrRJervis.