PORT-AU-PRINCE, Haiti — The United Nations has warned that it will cut off shipments of free medicine beginning immediately to any Haitian hospitals that it finds are charging patients.

When the catastrophic earthquake struck Jan. 12, authorities immediately decided to make all medical care free. More than 200 international medical relief groups have sent in teams to help, and millions of dollars of donated medicine has been flown in.

U.N. officials told The Associated Press that about a dozen hospitals have begun charging patients for medicine. The officials said they could not immediately provide the names of the hospitals but said they were in several parts of the country.

"The money is huge," said Christophe Rerat of the Pan American Health Organization, the U.N. health agency in the region. Hospitals don't need to charge patients to pay their staff, because Haitian Health Ministry employees are getting paid with donated money, Rerat added.

Haiti now has about 90 hospitals, including public and private hospitals and field hospitals. A member of the Haitian government commission created to deal with the medical crisis, Dr. Jean Hugues Henry, said he had no knowledge of any hospitals charging for services.