A 45-year-old Mexican migrant died on Monday in the custody of United States Customs and Border Protection, an event that was sure to intensify pressure on an agency overwhelmed by record numbers of migrant families crossing the border, while its health and safety standards have come under harsh public scrutiny.

The migrant, who was not identified, had been apprehended on Feb. 2 by the police in Roma, Tex., near a port of entry into the United States, and requested medical attention. He was found to have cirrhosis of the liver and congestive heart failure, the agency said in a statement, and was hospitalized twice while in custody — the second time spending two weeks in the intensive care unit of the McAllen Medical Center. He died there around 9 a.m. Monday.

The death came less than two months after 7-year-old Jakelin Caal Maquin and 8-year-old Felipe Gomez Alonzo also died in the agency’s custody, in December, amid three straight months of record-breaking numbers of migrant families entering the country. Both had shown symptoms of illness after they were taken into custody along the Southwest border, and their deaths prompted widespread condemnation from members of Congress and the public. The agency soon after announced new medical checks for children, and a temporary infusion of support from other federal agencies, including the Coast Guard and the United States Public Health Service.

Kirstjen Nielsen, the Homeland Security secretary, has requested $800 million from Congress to address the influx of migrant children and families, calling it a “humanitarian crisis.” The money would go toward staffing, supplies and enhanced facilities, among other things.