Hundreds of migrants are stranded in South and Central America after outgoing president Barack Obama ended a policy that had created a path to legal residency for thousands of Cubans who reached US soil.

Elaine Miranda and her partner, Marcos, embarked on a journey involving rough seas and trekking through South America eight months ago.

They felt certain that the $5,000 they spent on transport and people smugglers would be worth it, but the day after they crossed Mexico's southern border, the US suddenly repealed it's "wet foot, dry foot" policy.

Cubans seeking to stay in the US will now have to pass a "credible fear" process and present documentation proving they face a real threat in their country. The outcome is far from certain and can include lengthy stays in detention.

"I didn't leave Cuba because of my economic circumstances. And I didn't leave to chase the American dream," Elaine told Al Jazeera in Tapachula.

"I'm looking for the Cuban dream, which is freedom."

Pro-migrant activists say that Cuban politicians who pressed for the policy change to slow human trafficking are mistaken.

"It's a decision that's gravely affecting this group of people. This pronouncement won't stop migration," Luis Villagran, a migrant rights activist, told Al Jazeera.

"Nor will Donald Trump's presidency be able to stop migration. No one can stop it."

Elaine and Marco are now desperate to buy a little more time to present official documents required to avoid immediate deportation from Mexico.

"I'm not asking for any help. All of us are just asking to get to the US border and be let in," Elaine said.

"We're asking not to be sent back to Cuba, that would be the end of us."

Obama said the Cuban Medical Professional Parole Program, which was started by President George W. Bush in 2006, is also being rescinded.

The measure allowed Cuban doctors, nurses and other medical professionals to seek parole in the US while on assignments abroad.

The president said those doctors can still apply for asylum at US embassies around the world.

People already in the US and in the pipeline under both "wet foot, dry foot" and the medical parole programme will be able to continue the process towards getting legal status.