Spanish unions are holding a general strike to protest against labour reforms which the new government hopes will help cut unemployment, - BBC reported.
Road, rail and air transport are all due to be affected, with domestic and European flights cut to a fraction of their usual volume.
Mariano Rajoy's conservative government is to unveil measures on Friday to save tens of billions of euros.
The strike is the government's first big challenge since taking office.
Scuffles broke out between protesters and police as workers from Spain's largest unions picketed at the capital's bus depot early on Thursday.
The interior ministry said a total of 58 people were detained and nine were injured.
