Scuffles broke out between protesters and police as workers from Spain's largest unions launch a general strike on Thursday against unpopular austerity measures.
Around 100 picketers gathered early Thursday morning in front of the Fuencarral bus depot to protest labor reforms planned by the ruling People Party.
Transport and other public services are expected to be disrupted across the nation of 47 million on Thursday, as workers show their opposition to job losses and spending cuts.
The labor reforms will make it cheaper to fire workers and more difficult to implement inflation-linked salary hikes. The measures will also cap severance pay and will limit collective bargaining agreements.