Cuban leader Fidel Castro said two Cuban soldiers who killed an army officer during a failed attempt to hijack an airplane to escape from the island were encouraged by the prospect of impunity in the United States.

In an editorial e-mailed to journalists on Monday, Castro, 80, described last week's attempted hijacking as "a consequence of freeing the monster of terror."

He was referring to an American judge's recent decision to free Luis Posada Carriles, an anti-communist militant wanted in Cuba and Venezuela in the 1976 bombing of a Cuban airliner that killed 73 people.

"The impunity and the material benefits that have been rewarded for nearly half a century for all violent action against Cuba stimulate such acts," said the editorial, the fifth attributed to Castro since he since he disappeared from public view more than nine months ago.

"It only takes the stunning liberation of a known terrorist and death again is visited upon our homes," the statement said.

Castro, who has ruled Cuba for more than 40 years, announced in July he had undergone emergency intestinal surgery and was ceding his presidential functions to his 75-year-old brother Raul, the defense minister and his presumed successor.

Since then the elder Castro has only appeared in photos and videos released by government news outlets, but senior Cuban officials have been giving increasingly optimistic reports about his recovery and in recent weeks he has been penning a series of messages.

The United States has long refused to hand over Posada, who is awaiting trial in the United States on immigration fraud charges. He has been held under house arrest at his family's home in Miami since a judge in Texas released him on bond last month.

As well as the 1976 bombing, Cuba accuses Posada of orchestrating a string of 1997 Havana hotel bombings, including one that killed an Italian tourist.

Posada denies involvement in both cases.

Last week, three Cuban soldiers deserted their military post, killing a sentry and wounding a second before taking off with automatic rifles.

The government says one of the soldiers was captured before the hijacking attempt. But the other two commandeered a city bus with eight people aboard and forced the driver to travel to the Havana airport. Once there, the soldiers marched the group aboard an empty plane and demanded to be flown to the United States.

Castro said the sentry was shot four times. He said both deserters had been wounded, and one was shot.

"Now many people abroad are awaiting for the reaction of the courts and the Council of State before a people profoundly indignant by what has happened," Castro wrote, referring to widespread speculation about the trial and possible death sentences for the soldiers.

"A great deal of serenity and a cool head are needed to face these problems," he added.