Flags flew at half-mast on Thursday as Greek authorities declared three days of mourning following a sea disaster that left at least 78 dead with hundreds still feared missing. Rescuers saved 104 passengers - including Egyptians, Syrians, Pakistanis, Afghans and Palestinians, mostly men and including eight minors - but authorities fear that hundreds of others may have been trapped below deck on a fishing boat which sank on Wednesday in deep waters off the Greek coast.