The documents, from the U.S. Agency for International Development, were not classified as secret but contained details about a $6 million grant program, El Nuevo Herald reported Sunday.
The documents included applications from various non-governmental organizations in Cuba for a USAID program to train up-and-coming leaders of the groups. The applications were sent from Washington, D.C., to U.S. diplomats in Cuba for their review. U.S. officials fear the documents may have been intercepted by Cuban intelligence services.
One of the applicants, who spoke on condition of anonymity, said the documents he submitted for the grant contained the complete history of his work with pro-democracy groups in Cuba, some names of possible trainees and where they might be trained.
USAID spokesman Karl Duckworth defended the error, noting that nothing about the program is even considered confidential.
"We simply carry out programs in a discreet manner to help ensure the safety of all those involved," he said.
A USAID contractor, Alan Gross, is serving 15 years in a Cuban prison for delivering three satellite telephones to Cuban Jews so they could have uncensored access to the Internet.
More than 20 agencies are believed to have applied for the funding by the Aug. 9 deadline. After the mistake was discovered, USAID said the NGOs could withdraw their applications if they considered the risks unacceptable. None did.
A few weeks later, every NGO received a letter from USAID saying their applications had been rejected.