VATICAN CITY (Reuters) - Pope Francis, speaking after some 700 migrants were feared dead in the Mediterranean, on Sunday appealed to the international community to take swift and decisive action to avoid more tragedies.

"They are men and women like us, our brothers seeking a better life, starving, persecuted, wounded, exploited, victims of war. They were looking for a better life," he told tens of thousands of people in St. Peter's Square for his Sunday noon address.

"Faced with such a tragedy, I express my most heartfelt pain and promise to remember the victims and their families in prayer," he said, departing from his prepared text.

"I make a heartfelt appeal to the international community to react decisively and quickly to see to it that such tragedies are not repeated," he said, before asking the crowd to pray "for these brothers and sisters".

The latest disaster happened when a boat carrying migrants capsized off the Libyan coast overnight, in one of the worst disasters seen in the Mediterranean migrant crisis, officials said on Sunday.

(This story has been refiled to add dropped word "address" at the end of second paragraph)

(Reporting By Philip Pullella; Editing by Jon Boyle)