Cuba has returned to the United States a Hellfire missile that had been wrongly shipped to Havana two years ago.
The missile, which did not contain explosives, had been shipped to Spain for a Nato training exercise, the Wall Street Journal said.
It was then taken to Germany and eventually to Charles de Gaulle Airport in Paris for onward delivery to Florida.
It was instead loaded on to an Air France flight to Havana.
The incident could have led to a serious loss of military technology, officials said.