Hundreds of thousands of people rallied in cities and towns across Greece on Friday to demand justice on the second anniversary of the country’s deadliest-ever train crash, and striking workers grounded flights and halted sea and train transport.

Violence on Friday marred a huge demonstration in Athens to mark the second anniversary of the country's worst rail tragedy, with firebomb-wielding youths clashing with riot police outside parliament.

Air, sea and train transport was halted and mass protests were planned in Greece on Friday in anger over a perceived lack of justice two years after the country's worst-ever train crash killed 57 people.