The 5,000-word letter focuses on four themes: pain, gratitude, encouragement and praise.

All people of goodwill have a duty to help vulnerable women and other victims of human trafficking escape from forced sexual slavery, the pope wrote in a prologue of a new book on the suffering of women forced into prostitution.

The pope's appeal came after what authorities have called the worst shipwreck on the Mediterranean this year.

With the recent appointments of Matteo Bruni as the new director of the Holy See Press Office and Cristiane Murray as vice director, the Vatican is taking another step forward in its continuing efforts to reform its communication structures.

Pope Francis urged Syrian President Bashar Assad to put an end to his country's eight-year-long conflict and seek reconciliation for the good of the nation and its vulnerable people.