WASHINGTON (AFP) - Pope Francis played a vital role in bringing Cuba and the United States to the negotiating table, making a "personal appeal" to the nations' leaders, a US official said Wednesday.

The pontiff "sent that letter directly to President (Barack) Obama, and separately he communicated through a letter directly to President (Raul) Castro early this summer," a move that gave "greater impetus and momentum" in the process to normalize relations, the senior administration official said.