Migrants arriving as the US border are facing continuing uncertainty amid the chaos of Donald Trump’s reversal of a policy separating immigrant children from their parents.

A senior Trump administration official said about 500 of the more than 2,300 children separated from their families at the border have been reunited since May, but it is unclear how many children are still being detained with their families.

Immigrants like Ever Castillo and Diva Funes were among those affected by the mixed signals from the US.

The couple, from Comayagua, Honduras, arrived at the border on Thursday and presented themselves for asylum with their five children, aged one to 12.

Diva Funes holds the hand of her four-year-old son Evercito
Diva Funes holds the hand of her four-year-old son Evercito (David J Phillip/AP)

Mr Castillo said they did not know about the family separation policy when they began hitchhiking to the US two weeks ago.

He said Border Patrol agents told them they would be separated if they entered the US, and they opted to walk back across the international bridge into Reynosa, Mexico.

“I said, ‘better that we head back to my country’,” said Mr Castillo.

A seven-year-old boy and his migrant mother who had been separated a month ago were reunited after she sued in federal court and the Justice Department agreed to release the boy.

The two were reunited at about 2.30am on Friday at Baltimore-Washington International Airport, hours after a Justice Department lawyer told a US District Court judge the child would be released.

Beata Mariana de Jesus Mejia-Mejia is reunited with Darwin
Beata Mariana de Jesus Mejia-Mejia is reunited with Darwin (Patrick Semansky/AP)

The mother, Beata Mariana de Jesus Mejia-Mejia, had filed for political asylum after crossing the border with her son Darwin, following a trek from Guatemala.

She said she started crying when the two were reunited and that she is never going to be away from him again.

Other immigrants who remain locked up and separated from their families are struggling to stay in touch with children who are in many cases hundreds of miles apart.

A 31-year-old Brazilian man held in Cibola County Correctional Centre in New Mexico said he did not know when he would see his nine-year-old son again.

The father said he had spoken to his son once by phone since they were separated 26 days before.

The man, who is seeking asylum, spoke on condition of anonymity because he said in Brazil he is being hunted by a criminal gang for failure to pay an 8,000 dollar debt, and fears retribution.

The man said he worried about his son, who only speaks Portuguese. “He cried. He was so sad,” the father said. “I had promised him it would only be three to five days.”

He said he travelled to the US planning to find work and then send for his wife and their other son, who is three.

He and his nine-year-old took a flight to Mexico City then made their way to the border. Trying to cross illegally near San Ysidro, California, the two were picked up by border agents.

He and his son were taken to a detention centre with many other families.

“For two days all we were given were Doritos, cereal bars and juice.”

Then he was told his son would be taken to a facility for minors but they would be separated no more than five days.

“I didn’t want to scare him. I said, ‘Look son, I’ll just be gone three days, five at the most, and then I will see you again’. He cried and hugged me. He is a good kid. He had never been separated from me or his mum.”

Ten days later, the father learned his son had been taken to an Office of Refugee Resettlement in Chicago. He called a legal hotline and an immigration lawyer eventually helped arrange a 20-minute phone conversation with the boy.

Meanwhile, the boy already had made contact with his mother back in Brazil.

“He cries a lot and wants to leave,” said the mother, who is 31 and cleans office buildings. “He is calmer now, but he still wants to get out of there.

“It’s horrible. Awful. The kids are suffering. (Parents) are too.”