The Democracy Movement has organized several such flotillas in the past, including two that used fireworks. But this time, the 43-foot “Musele Prince” was firing 8-inch shells, compared to the 6-inch fireworks used in the past.

Cuba’s Foreign Ministry for the first time Friday officially condemned the flotilla as a “provocation” and confirmed that the Cuban government had expressed its concerns to Washington.

The U.S. government “is perfectly informed of the Cuban government’s concern with this type of provocation,” René Mujica, a top analyst in the ministry’s North American affairs section, told journalists in Havana.

The Communist Party’s Granma newspaper also reported Friday that five persons drowned when their boat sank off the coast of Santa Cruz del Norte, about 30 miles east of Havana, as they tried to escape the island.

Another 18 would-be refugees were rescued by the military and oil workers during the incident in late November, Granma added. Cuba’s government-controlled news media seldom reports on such incidents.

The State Department, meanwhile, confirmed an El Nuevo Herald report earlier this week that U.S. officials had urged the Democracy Movement and the Cuban government “to exercise caution and restraint” during Friday’s fireworks.

“We have also made it clear to Cuban authorities as well as participants in this event that the U.S. government would punish any violation of U.S. laws,” spokesman William Ostick said in a statement.

Ramon Saul Sanchez broke away from one of the previous Democracy flotillas and entered Cuban territorial waters. U.S. prosecutors put him on trial, but he was found not guilty.