(Pope Benedict XVI meets former Cuban leader Fidel Castro in Havana March 28, 2012. REUTERS/Alex Castro )

Pope Benedict called for an end to the U.S. trade embargo against Cuba and met with revolutionary icon Fidel Castro on Wednesday as he ended a trip in which he urged the communist island to change.

He also spoke at a public Mass in Havana’s sprawling Revolution Square where the Vatican said 300,000 people gathered to hear the 84-year-old pontiff.

In a trip laced with calls for change in Cuba, his last message was aimed at the United States, its long-time ideological foe, which for 50 years has imposed a trade embargo trying to topple the Caribbean island’s communist government.

Speaking in a departure ceremony at a rainy Havana airport, Benedict said Cuba could build “a society of broad vision, renewed and reconciled,” but it was more difficult “when restrictive economic measures, imposed from outside the country, unfairly burden its people.”