An official statement said the men were tried "with full respect for their ... basic rights," convicted Tuesday and shot dead at dawn Friday.

Another four of the men involved in the hijacking of the ferry with some 40 people aboard were sentenced to life in jail, and one man to 30 years in prison. The three women who took part were sentenced to five, three and two years respectively.

A swift appeal was nixed by the Council of State, which is led by President Fidel Castro, the statement added.

The ferry was seized April 2 -- a day after a Cuban plane was hijacked to the United States -- and sailed halfway to the Florida coast before it ran out of fuel and was towed back to Cuba.

Eleven people reportedly armed with knives and hand guns took over the 15-meter (50-foot) long vessel and forced it to sail toward the United States.

The commuter craft and spent 20 hours in open waters before it was towed back to the port of Mariel 50 kilometers (30 miles) from Havana.

Cuba has been staunchly critical of the US policy dubbed "wet foot, dry foot," of granting asylum and US residence to any Cuban who manages to set foot on US soil, but turning back those stopped at sea. Havana claims the US policy encourages illegal and often dangerous emigration attempts.

Havana explained the death sentences saying they took into account "the seriousness of the events for the country's security, target of a sinister program of provocations fueled by the most extremist sectors of the US government and the Miami terrorist mafia with the lone objective of creating conditions and pretexts for aggression against our country."

Dissident Elizardo Sanchez, who leads the Cuban Committee for Human Rights and National Reconciliation, said he was "absolutely troubled, because by no means was a death penalty justified."

"It is a regrettable return" to capital punishment, Sanchez told AFP.

The executions followed a week of harsh sentences -- from six to 28 years in prison -- doled out to 75 dissidents rounded up in a recent crackdown and accused of being threats to state security, after trials lasting a few hours.

Prominent dissidents including journalist Raul Rivero and economist Marta Beatriz Roque were sentenced to 20 years in jail. Dissident physician Oscar Elias Biscet was sentenced to 25.

International condemnation has come from the United States and the European Parliament, which demanded the immediate release of the dissidents. Cuba insisted the sentences were an appropriate response to aggressive US policy toward the only communist, one-party system in the Americas.

"We have the right to defend our own political system and our right to self-determination," Foreign Minister Felipe Perez Roque told an almost four-hour press conference Wednesday, which included sheafs of documents and testimony from state agents who infiltrated dissident groups.

"We were patient, tolerant, but the activities of James Cason (the head of the US Interests Section in Havana) have forced us to enforce our laws," Perez Roque said, charging that the dissidents were paid agents of the United States.

The agents presented as having infiltrated dissident groups claimed in their testimony they were paid in US dollars by various NGOs or others affiliated with the US Agency for International Development (USAID), and were given free access to the US Interests Section.

In Washington, the United States said it was pleased that Peru, Uruguay and Costa Rica introduced a resolution on Cuba to the UN Human Rights Commission urging Havana to allow a visit by the high commissioner's personal representative.

A State Department official added privately: "we condemn hijacking, which is an act of terrorism. (But) we believe strongly in the due process of law, including right to counsel and have a good amount of time to prepare a defense and proceedings with transparency and accountability."

"We are concerned that these executions may have been a result of summary proceedings which are a hallmark of totalitarian dictatorships like Cuba's."