HOUSTON (AP) — U.S. immigration authorities said Wednesday that they have done new medical checks on nearly every child in Border Patrol custody after the death of a second youngster in the agency's care in the span of less than three weeks.

Authorities did not disclose the results of the examinations.

An 8-year-old boy identified by Guatemalan authorities as Felipe Gómez Alonzo died on Christmas Eve just before midnight. He had been in the custody of U.S. Customs and Border Protection with his father since Dec. 18.

The boy suffered from a cough, "glossy eyes," fever and vomiting and was hospitalized twice on Monday with what was initially diagnosed as a cold, the agency said in a statement. The cause of death was under investigation.

Officials at the Department of Homeland Security, the Border Patrol's parent agency, said that almost all checks ordered in reaction to the boy's death had been completed.

Some children detained in more remote areas were re-screened by emergency medical technicians or Border Patrol agents, officials said. In other places, some children were taken to medical facilities.

Homeland Security would not say how many children are in Border Patrol custody.

The department also wouldn't say why Felipe and his father were detained for almost a week, an unusually long time, or why they were placed back in detention — at a Border Patrol highway checkpoint — after being released from the hospital.

Another Guatemalan child in U.S. custody, 7-year-old Jakelin Caal, died on Dec. 8 after she began vomiting. U.S. officials said she had walked for days in the desert without food or water, but her family disputed that.

Her death — which brought down heavy criticism on U.S. immigration authorities — is also under investigation.

Immigration advocates and human rights groups sharply criticized CBP in the wake of Felipe's death.

Margaret Huang, executive director of Amnesty International USA, said the Trump administration's "policies of cruelty toward migrants and asylum-seekers at the border must cease immediately before any more children are harmed."

CBP said in a statement late Tuesday that it needs the help of other government agencies to provide health care.

The agency "is considering options for surge medical assistance" from the Coast Guard and may request help from the U.S. Department of Health and Human Services, the Department of Defense and the Federal Emergency Management Agency.

With border crossings surging, CBP processes thousands of children — both alone and with their parents — every month. According to CBP statistics, border agents detained 5,283 children unaccompanied by a parent in November alone. Agents last month also apprehended 25,172 "family units," or parents and children together.

CBP typically holds children for no more than a few days. Youngsters who arrive unaccompanied are turned over to longer-term facilities operated by the HHS. The Associated Press reported this month that 14,300 children were being detained by HHS, most in facilities with more than 100 kids.

U.S. Customs and Border Protection Commissioner Kevin McAleenan said Wednesday that the agency has more than 1,500 emergency medical technicians on staff and that officers are taking dozens of sick children to hospitals every day.

"This is an extraordinarily rare occurrence," McAleenan told "CBS This Morning" of the recent child deaths. "It's been more than a decade since we've had a child pass away anywhere in a CBP process, so this is just devastating for us."

Border officers remain on the job despite the partial government shutdown over President Donald Trump's demand for funding for a border wall.

CBP typically detains adult immigrants for no more than a few days when they cross the border before either releasing them or turning them over to U.S. Immigration and Customs Enforcement for longer-term detention.

More From KGAB