Greek authorities picked up 56<span style="font-weight: bold;"> </span>survivors from the sea on Monday during a large rescue operation after a vessel carrying an unknown number of migrants sank off the southern island of Crete. <br />''<br />''The mishap left three migrants dead that included a woman and two children.<br />''   <br />''The Coast Guard officials said, efforts are on to locate other people who might be in the water. <br />''<br />''They said, a Greek naval frigate and an air force helicopter were taking part in the search, together with two Coast Guard boats and three merchant ships.<br />'' <br />''Greece's east Aegean Sea islands are the typical destination of thousands of asylum-seekers from the West Asia, Africa and Asia who cross illegally from the nearby Turkish coast in hope of finding a better life in the European Union.<br />