MADRID — In a development that raises a host of ethical issues, Spain announced it had obtained a scarce U.S.-made experimental Ebola drug to treat a Spanish missionary priest infected with the killer virus.

The Health Ministry statement came less than a week after the U.S. Centers for Disease Control and Prevention said there were virtually no doses available of the drug that was used to treat two Americans with the disease.

The drug’s maker, Mapp Pharmaceutical Inc. of San Diego, says “very little of the drug is currently available” and that is cooperating with government agencies to increase production as quickly as possible.

Nigerian officials say they had asked U.S. health authorities about getting the Ebola drug but were apparently not helped.

There is no known cure or licensed treatment for Ebola, which has killed over 960 people in the current outbreak in West Africa. The World Health Organization has called the Ebola outbreak — which emerged in Guinea in March and has since spread to Liberia, Sierra Leone and possibly Nigeria — an international health emergency and urged nations worldwide to battle the disease.

The ethical questions surrounding experimental Ebola drugs and vaccines were being debated Monday during a teleconference of medical ethicists and other experts organized by the U.N. health agency.

In a statement provided Monday, the Spanish Health Ministry said the ZMapp drug was obtained in Geneva this weekend with permission from the company and brought to Madrid to treat Miguel Pajares. The 75-year-old priest was evacuated from Liberia and placed in isolation Thursday at Madrid’s Carlos III Hospital.

Two Americans diagnosed with Ebola in Liberia and evacuated back to the United States have been treated with the drug. One of them, Dr. Kent Brantly, said last week that his condition was improving and the husband of the aid worker being treated with Brantly said the same thing. Both are in isolation at an Atlanta hospital.

It was not exactly clear how Spain got the drug.

Spain said it obtained permission from the laboratory developing the drug and, under an agreement between WHO and the Doctors Without Borders charity group, imported the drug from Geneva where it said a dose had been available. The ministry said Spain sought the drug under legislation permitting use of unauthorized medication in patients suffering from a life-threatening illness who cannot be treated satisfactorily with any authorized drug.