Subway workers in Athens will strike on Friday for the first day after the summer holidays. Two lines of the Athens metro will be on a 24-hour strike against possible staff reductions. Tram workers will also strike for three hours. Greek air traffic controllers announced a four-hour strike for Sunday from 14:00 to 18:00, which would potentially close all airports in Greece and cancel flights. Greece authorities are implementing austerity measures stipulated by the IMF and EU.