ALAMOGORDO, N.M. (Reuters) - A Congressional delegation of Democrats touring a Border Patrol facility in New Mexico on Monday warned President Donald Trump against circumventing Congress and diverting already appropriated money toward building a wall on the U.S.-Mexico border.

U.S. Representatives Xochitl Torres Small (D-NM) and Joaquin Castro (D-TX) exit after touring a Border Patrol substation with other legislators, investigating the circumstances that led to the death of Felipe Gomez Alonzo, an 8-year-old Guatemalan boy who died in immigration detention, in Alamogordo, New Mexico, U.S., January 7, 2019. REUTERS/Julio-César Chávez

“He can expect a strong and swift challenge from all of us and other members of Congress, and from the American people,” said U.S. Representative Joaquin Castro, when asked about Trump’s planned address to the nation and his visit to the border on Thursday.

Castro, a Democrat from San Antonio, is leading a Congressional delegation visiting the Border Patrol facility in Alamogordo, New Mexico to investigate the death of 8-year-old Felipe Gomez Alonzo, the second child to die in December after being apprehended crossing the border illegally.

Democrats, who now control the U.S. House of Representatives, have rejected the Republican president’s demand for $5.7 billion to help build a wall. Without a deal on that sticking point, talks to fund the government - now in the 17th day of a shutdown - have stalled.

Trump has vowed not to back off his 2016 campaign promise to build a wall that he believes will stem illegal immigration and drug trafficking. He promised during the campaign that Mexico would pay for the wall. Mexico has refused to do so.

Democrats in Congress say a wall would be expensive, inefficient and immoral.

In New Mexico, Border Patrol agents walked the Congressional delegation through the holding areas of the Alamogordo station, which Representative Jerry Nadler, a Democrat from New York, said were “miraculously” empty.

Castro said the Border Patrol did not provide a report about Gomez’s death nor did they tour the hospital where he was treated for a cold and then released with a prescription for antibiotics and ibuprofen. The boy died shortly after his release.

“We know that CBP is woefully under equipped in terms of its standards of medical care, but we also need to find out whether the doctors in the hospital - how responsible they were in terms of that case,” Castro said.

The Border Patrol itself has said their facilities are not properly equipped to hold families, Castro said. “I think all of us who look at what they have here believe that that is true.”

U.S. Representative Veronica Escobar, a Democrat from El Paso, said the area where Gomez and his father turned themselves over to Border Patrol is on American soil and already fenced.

“The wall only pushes people out to more dangerous, treacherous crossings, creating even more death,” she said.

Illegal crossings at the southern border have dropped dramatically since the late 1970s, but in recent years more Central American families and unaccompanied children are migrating to the United States. Many are released after turning themselves into border agents and requesting asylum, a legal process that can take years to resolve in U.S. immigration courts.