Wednesday's strike disrupted public transport, halted ferry and train services, shut down state-run schools and left state hospitals and the ambulance service functioning with emergency staff.
Dozens of flights were canceled or rescheduled as air traffic controllers were to walk off the job for three hours from noon in support of the labor action.
The strike comes during tough negotiations between the government and debt inspectors from the International Monetary Fund, European Central Bank and European Commission, known collectively as the troika, over what measures are needed to plug a budget gap next year.
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