WASHINGTON — Fernando Murillo was typical of the young Latin Americans deployed to Cuba by a U.S. agency to work undercover. He had little training in the dangers of clandestine operations — or how to evade one of the world’s most sophisticated counter-intelligence services.

Their assignment was to recruit young Cubans to anti-government activism, which they did under the guise of civic programs, including an HIV prevention workshop. Murillo was instructed to check in every 48 hours and was provided with a set of security codes. “I have a headache,” for instance, meant the Costa Rican thought the Cubans were watching him and the mission should be suspended.

Over at least two years, the U.S. Agency for International Development — best known for overseeing billions of dollars in U.S. humanitarian aid — sent nearly a dozen neophytes from Venezuela, Costa Rica and Peru to gin up opposition in Cuba. The danger was apparent to USAID, if not to the young operatives: A USAID contractor, American Alan Gross, had just been hauled away to a Cuban jail for smuggling in sensitive technology. He remains there still.

USAID hired Creative Associates International, a Washington-based company, as part of a civil society program against Cuba’s communist government. The same company was central to the creation of a “Cuban Twitter” — a messaging network revealed in April by The Associated Press, designed to reach hundreds of thousands of Cubans.

According to internal documents obtained by the AP and interviews in six countries, USAID’s young operatives posed as tourists, visited college campuses and used a ruse that could undermine USAID’s credibility in critical health work around the world: An HIV-prevention workshop one called the “perfect excuse” to recruit political activists, according to a report by Murillo’s group. For all the risks, some travelers were paid as little as $5.41 an hour.