SAN JUAN, Puerto Rico (AP) _ Four U.S. residents arrested in an alleged plot to kill Cuban President Fidel Castro were freed on bail Monday.

U.S. District Judge Juan Perez released the three Miami residents and a New Jersey man on bails ranging from $30,000 to $50,000.

The men, all of Cuban heritage, were arrested on Oct. 30 after their boat ran into mechanical difficulty off the coast of Puerto Rico. Seventy rounds of ammunition and two rifles were found on the boat, according to a criminal complaint.

Suspect Angel Manuel Alfonso said his group planned to assassinate Castro at last weekend's Ibero-American Summit on Margarita Island in Venezuela, the complaint said.

A judge agreed to a charge of arms smuggling, which carries a maximum sentence of five years' imprisonment. The case will now go before a grand jury.

The boat used by the suspects was listed in a Florida registry as being owned by Juan Antonio Llama, a director of the Cuban American National Foundation.

The Miami-based exile group has been blamed by the Cuban government for a series of recent hotel bombings in Cuba which killed one person. The foundation has denied any responsibility for the bombings.