As the prisoners age, their physical and mental health needs are increasingly challenging, the leader of a visiting delegation said.GUANTÁNAMO BAY, Cuba — A senior official with the International Committee of the Red Cross issued a rare statement of alarm on Friday about deteriorating health conditions and inadequate preparations for aging prisoners at Guantánamo Bay.The U.S. military must do a better job of providing care for prisoners who are “experiencing the symptoms of accelerated aging, worsened by the cumulative effects of their experiences and years spent in detention,” Patrick Hamilton, the head of the Red Cross delegation for the United States and Canada, said in the statement.In March, Mr. Hamilton and other delegates made a routine quarterly visit to the detention facility, the organization’s 146th since the wartime prison opened in January 2002. He said the detainees’ “physical and mental health needs are growing and becoming increasingly challenging.”“Consideration must be given to adapting the infrastructure for the detainees’ evolving needs and disabilities, as well as the rules that govern their daily lives,” said Mr. Hamilton, who had last visited the prison in 2003, when 660 men and boys were held there. Today, 30 detainees remain.Red Cross officials generally do not comment publicly on the conditions at the detention facility, preferring to keep their communications with the U.S. government confidential.Ordinarily, quarterly visits include meetings with the detention facility commander, who is currently a brigadier general with the Michigan National Guard. Members of the delegation, which generally includes a doctor, also meet with detainees, interview those who will soon be released and deliver messages from family.Mr. Hamilton said military officials at Guantánamo were “offering some temporary solutions” to the prisoners’ increasing physical and mental health needs.He urged the Biden administration and Congress to, as a priority, “find adequate and sustainable solutions to address these issues.”Lawyers for some of the prisoners, particularly those who spent years in harsh, secret C.I.A. custody before Guantánamo, have said detainees have brain damage and disorders from blows and sleep deprivation, damaged gastrointestinal systems from rectal abuse and issues possibly linked to prolonged shackling and other confinement.One of the most debilitated prisoners is Abd al-Hadi al-Iraqi, who is in his 60s and is the prison’s oldest detainee. He has undergone six operations on his spine and back at Guantánamo Bay since 2017 by Navy medical teams who were airlifted to the base.His lawyer, Susan Hensler, said Friday that Mr. Hadi was recently diagnosed with “severe osteoporosis” that likely contributed to problems in his most recent operation, in November. Doctors inserted metal inside his back, but the device slipped and screws became loose, she said. Navy doctors plan to bring a team to the base this year for another surgery, using bigger screws.The Red Cross statement comes less than a month after a group of United Nations investigators made public a complaint they had presented to the United States on Jan. 11 about health care provisions at the prison, and for Mr. Hadi in particular.Mr. Hamilton said the United States needed to adopt a “more comprehensive approach” to detainee health care. “All detainees must receive access to adequate health care that accounts for both deteriorating mental and physical conditions — whether at Naval Station Guantánamo Bay or elsewhere. This includes cases of medical emergencies.”“At the same time, consideration must be given to adapting the infrastructure for the detainees’ evolving needs and disabilities, as well as the rules that govern their daily lives,” he said.Government employees, who were not authorized to be identified by name, have complained about air conditioning problems at the prison for detainees through the month of Ramadan, which is ending.The military had no immediate comment on either the Red Cross concern or the air conditioning issue.The Red Cross official also urged the Pentagon to grant its prisoners longer, more frequent phone calls with family members, “bearing in mind the total absence of in-person visits.”Lawyers have said detainees are generally entitled to speak with family members four times a year.