Night had fallen on one of the most dangerous cities in one of the most dangerous countries on Earth and José Mendoza was making his escape.

“So much killing,” the 32-year-old said as he began his punishing 2,000-mile odyssey to the United States on foot.

Mendoza lived in San Pedro Sula, a gang-ridden industrial hub of about 700,000 in north-western Honduras where body-strewn tabloid front pages provide a grotesque daily reminder of the carnage.

But – like thousands of violence-weary compatriots – he had decided he could bear the bloodletting no more and headed north, through Guatemala and Mexico, to the United States.

“There are no reasons to stay here – only to leave,” said Giovanni Rodríguez, a Honduran author who draws inspiration for his work from his days as a corpse-counting crime reporter on the mean streets of San Pedro Sula.

For all the dangers fueling the exodus from Central America, Donald Trump now wants to turn the region into a destination for the thousands of unwanted asylum seekers he is battling to turn away from the United States.

This week Trump officials unveiled the latest in a slew of highly controversial agreements and policies designed to stop migrants and asylum seekers such as Mendoza reaching the southern border.

The deal – announced by Trump and his Honduran counterpart, Juan Orlando Hernández, on Wednesday – will allow the US to return asylum seekers from third countries to the violence-stricken Central American nation which has the US state department’s second-highest travel warning.

That followed similar accords with El Salvador and Guatemala, the two other countries that form Central America’s “Northern Triangle”.

A man lies dead after a shooting in San Pedro Sula, Honduras, on 2 June 2018. Photograph: Edgard Garrido/Reuters

Mexico has also intensified its immigration clampdown since June after economic threats from Trump, causing a 56% drop in the arrival of undocumented migrants to the US’s southern border.

Speaking at the UN general assembly this week, Trump boasted he was taking “very unprecedented action to stop the flow of illegal immigration” and warned those heading north not to come, “because if you make it here, you will not be allowed in – you will be promptly returned home”.

US officials claim their hardline policies will protect migrants from the long and perilous journey through Central America and Mexico.

But critics say returning often vulnerable migrants from countries in Central America, Africa and the Caribbean to unprepared and often extraordinarily violent cities such as San Pedro Sula is a recipe for disaster.

Under this week’s agreement, Haitian or Congolese asylum seekers could be sent from the US to Honduras, for example, while Honduran asylum seekers could be sent to El Salvador or Guatemala under the previous deals with those countries.

Clara Long, an immigration researcher from Human Rights Watch, said: “As a protection scheme this is a nonsensical solution. As a scheme for keeping asylum seekers as far away from the US as possible it could be effective – and with very harmful consequences.

“El Salvador has a staggeringly high homicide rate, similarly Honduras. Guatemala isn’t as bad but it is still elevated. And these are countries from which hundreds of thousands of people are fleeing, many of them from targeted threats,” Long added.

Eric Olson, a Central America specialist from Washington’s Woodrow Wilson Centre, said Northern Triangle countries lacked even the most basic institutional infrastructure to receive so many rejected asylum seekers.

While the United States handled hundreds of thousands of asylum applications last year, El Salvador received just 20.

“What it does is put vulnerable, weak countries at greater risk, and migrants who have a legitimate claim to asylum are also put at greater risk. That is the bottom line,” Olson said.

“When you have a weak and unstable country to begin with … and you add to that burden, I think you create greater instability. Maybe if it were Switzerland it wouldn’t be a problem. But these are vulnerable, weak countries.”

Iduvina Hernández, a Guatemalan journalist and human rights activist, said she feared her country’s health system could collapse under the strain of the new arrivals.

African migrants protest during a march demanding humanitarian visas that would enable them to cross Mexico on their way to the US, in Tapachula, Chiapas state, Mexico, on the border with Guatemala, on 30 August 2019. Photograph: Isaac Guzman/AFP/Getty Images

“If the health system is [already] unable to provide services to Guatemalans, how can it possibly provide services to hundreds of thousands of people from Honduras and El Salvador as well?” she asked. “It will trigger a humanitarian crisis.”

Given the massive stress the US deals are likely to place on their countries, many wonder why El Salvador, Honduras and Guatemala have signed up to such schemes, details of which remain sketchy.

Hernández said she suspected the US-Guatemala deal was “a product of the [Guatemalan] president’s need for impunity”. Jimmy Morales, the country’s outgoing leader, came to power nearly four years ago promising to battle corruption but has himself become embroiled in scandal with a UN-backed anti-corruption commission forced from the country earlier this month.

There is similar speculation in Honduras, where President Hernández is caught up in a major drug trafficking investigation which will see his brother go on trial in the US next month.

Olson called such speculation “preposterous”, arguing it would be impossible for a US president to guarantee impunity to any foreign leader.

But the deals did underscore the lopsided nature of relations between the US and its far poorer regional neighbours who are massively reliant on it for trade, aid and remittances from their nationals who live there.

“I think it’s an indication of how vulnerable these countries are vis-a-vis the Trump administration. The US carries a huge stick,” Olson said. “There is too much at play for these small countries. They are just not in a position to resist the enormous pressure that the US puts on them.”

Trump has celebrated his migration deals as a major victory for his administration, this week claiming he had “sort of solved asylum”. “Mass illegal migration is unfair, unsafe and unsustainable for everyone involved,” Trump told the UN.

But Long warned his project to bar asylum seekers and migrants would ultimately fail. “Nothing is changing about the circumstances forcing people to flee or their desperation. But things are changing to make the outcomes worse.”

“In the last 10 years more Hondurans have died than in 10 years of civil war in El Salvador,” said Bartolo Fuentes, a Honduran migrant activist, who also believes Trump will be unable to stop migrants trying to outrun the killing.

“Sometimes our death rates have gone above Syria’s – and we don’t have the war.”