But then the rumours began. Juan — who asked that his full name be withheld for his safety — said he was falsely accused of passing secret government information to the United States. Cars started appearing outside his home to surveil him and his family.

So in December, Juan, his wife, his daughter and his granddaughter fled west to Medellin, Colombia, in the hope of finding safety.

In the months since, however, he has continued to receive threats. “You left the country with your family, traitor,” a man’s voice once growled through his phone. “We’re going to locate you, to make you pay.”

As a result, Juan has turned to a new system for migrants and asylum seekers hoping to relocate to the US: overseas migration processing centres.

In 2023, the US announced it would open centres in countries like Colombia and Guatemala to deter migrants and asylum seekers from attempting to reach its borders on foot.

The US Department of State says the migration processing centres — called “Safe Mobility” sites or “Movilidad Segura” in Spanish — will make the refugee application process quick and accessible.

But critics fear the centres may leave asylum seekers waiting in unsafe conditions abroad, vulnerable to the very dangers they fled.

Since arriving in Medellin, Juan said he has had to move five times for fear of being tracked down by those who wish to harm him.

“I have to leave here with my family due to insecurity,” Juan told Al Jazeera. “I don’t sleep at night.”

Tears started to slide down his cheeks. “I didn’t know this situation was going to be so serious.”

The first Colombian processing centre opened its doors on August 1 in Medellin. Another has since been established in Cali, and a third is set to open outside of Bogota.

But the website for the centres started accepting applications for appointments earlier in the year for Venezuelans, Haitians and Cubans. The application portal opened briefly in June and again for another day and a half in August.

Juan said he has checked the site every day, but he missed the August window. And when he arrived at Medellin’s Safe Mobility office to inquire about political asylum, he was turned away for not having an appointment.

A State Department official in Washington, DC, who asked to remain anonymous, told Al Jazeera the Safe Mobility centres are taking a “phased” approach to process people in an “orderly” way.

As of August 28, an estimated 28,000 people have applied for an appointment in Colombia alone, according to the official.

Of the limited number of migrants deemed eligible for entry into the US so far, most have been referred to the US Refugee Admissions Program (USRAP) — including 260 from Colombia.

Another 1,300 have been referred from Guatemala, where centres opened in June. And 570 came from Costa Rica, where officials recently opened online registration for Venezuelans and Nicaraguans.

But evaluating refugee applications has historically been a slow process for the US. Applicants must go through multiple screenings and extensive security vetting. Plus they must sit for an interview with US immigration officers, which can delay the process depending on which country the applicant is applying from.

The Refugee Coordination Center estimated the average timeline for claims stood at four years, as of March.

“For the [Safe Mobility offices] and lawful pathways for forcibly displaced people to be effective, they have to be fast,” said Sunil Varghese, policy director at the International Refugee Assistance Project.

“When someone is fleeing for their lives … they often can’t stay in one place.”

The State Department official told Al Jazeera they are looking to speed up processing significantly, with the goal of reducing it to a matter of months. People screened at the centres would already be determined eligible for refugee status, potentially speeding up their approval.

The number of Venezuelans resettled in the US as refugees has typically been low. Recent government statistics show the US admitted approximately 850 Venezuelans as refugees from October 2022 through July 2023 (PDF), despite a steady rise in displacement in the region.

But the Safe Mobility offices could boost those numbers.

“It will be a large contributor to the overall resettlement numbers to the US,” the State Department official said.

The administration of US President Joe Biden has committed to resettling 20,000 refugees from Central and South America in fiscal years 2023 and 2024, which would triple the annual number admitted.

The State Department official noted the Safe Mobility offices will not replace other ways people are referred to the US refugee programme, such as through nongovernmental organisations.

The centres are also expected to connect qualified migrants with other pathways to reach the US: work visas, the family reunification programme or the newer humanitarian parole option for Venezuelans, Cubans, Haitians and Nicaraguans.

Applicants are first screened remotely and then told whether they qualify for limited in-person interviews.

Sitting outside the Safe Mobility office in downtown Medellin last week, Yesica Cordoba spoke to Al Jazeera while her husband, Irvin, was inside for their appointment.

The couple fled Caracas, Venezuela, due to economic and political instability. Irvin had been detained briefly for taking part in large protests against President Nicolas Maduro’s government in 2017. After he escaped, a friend helped them resettle in Medellin a few months later.

With her two-and-half-year son, Donovan, on her lap, Cordoba explained that inflation in Colombia is severely straining her income. She works in a restaurant, but her rent is now double what she and Irvin paid when they first moved to Colombia, settling in a small place in a lower-end neighbourhood.

“Having a child, with two salaries, they’re not enough,” Cordoba told Al Jazeera.

She and Irvin have not heard anything back from the Safe Mobility office, but she said they were hopeful about work opportunities. They had considered relocating to other countries, but Cordoba explained their resources were too meagre to afford the move.

“Those options require money, which, at the moment, we do not have, and we do not know if we will ever have,” she said. “We are betting everything on Safe Mobility.”

But Varghese cautioned that while the Safe Mobility centres have the potential to help immigration proceedings, they are no substitute for access to asylum at the US-Mexico border, where some people flee for immediate assistance.

“There are going to be people who will not be able to wait even for a brief period safely,” he said. “That’s why international law requires that people be able to seek refugee protection at the borders also.”