US Border Patrol agents have found a three-year-old boy alone in a field in Texas at the Mexico border.

US Customs and Border Protection (CBP) said that the boy’s name and a phone number were written on his shoes when agents found him that morning.

The agency said it is trying to reach the boy’s family and that the boy “does not speak well enough to communicate”.

US broadcaster NBC News, which first reported the story, said the boy was crying and in distress when the agents found him near Brownsville, which is at the eastern edge of the US-Mexico border in South Texas’ Rio Grande Valley.

The child will most likely be sent to a facility for unaccompanied minors operated by the US Department of Health and Human Services.

CBP said that a Border Patrol agent purchased clothing for the child and that other officers watched movies and played games with him.

The Border Patrol apprehended nearly 9,000 unaccompanied minors just in March and more than 20,000 since January, as border crossings surged compared to recent levels. The agency said that it could not provide a breakdown by age.

Most minors are usually teenagers from Central America who travel north on their own, but some are young children who arrived with an adult relative or a human smuggler. And parents carrying infants or holding the hands of young children arrive daily.

That surge of families has put pressure on the Border Patrol, which says it does not have the staff or facilities to care for hundreds of children at a time.

While US authorities have ended the large-scale family separations that spurred outrage last year, the Border Patrol says it still must take children from adults who are not biological parents or legal guardians or when it suspects fraud or neglect.

Agency officials said this month that from April 2018 through most of March, the Border Patrol identified more than 3,100 parents and children it accused of making “fraudulent claims”.

During a March visit to the Border Patrol’s main processing centre in McAllen, reporters from The Associated Press saw a four-year-old boy sitting with adult staff watching cartoons. Authorities said the adult who brought the boy was not his parent and had a criminal record.