The corpses of 17 migrants were brought ashore in Sicily aboard an Italian naval vessel on Sunday along with 454 survivors as efforts intensified to rescue people fleeing war and poverty in Africa and the Middle East.

More than 5,000 migrants trying to reach Europe have been saved from boats in distress in the Mediterranean since Friday and operations are in progress to rescue 500 more, European Union authorities said on Sunday.

In some of the most intense Mediterranean traffic of the year, migrants who left Libya in 25 boats were picked up by ships from Italy, Britain, Malta and Belgium, assisted by planes from Iceland and Finland, the EU's border control agency Frontex said.