Thousands of striking workers marched today through more than 50 Italian cities to protest government reforms they say erode their rights.
The general strike, which has shut down basic services across the country, is the first by two of Italy's largest union confederations against a centre-left government.
Protesters clashed with police in some cities, including Rome and Milan.
Also in Milan, students dressed as Santa Claus jumped the fence at a regional government office building, in a protest that police dispersed with tear gas.
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Prime Minister Matteo Renzi said the right to strike must be protected, but insisted his tougher line is necessary to return the economy to growth and create jobs.
"The future belongs not to those who are afraid but those who have the courage and the desire to change," Renzi told a business forum in Istanbul.
In a sign of internal discord within his own party, some members of the Democratic Party joined the marches.
Stefano Fassina, a former deputy economics minister, told Italian news channel Sky TG24 it was important that someone from the party marched alongside the workers.
Susanna Camusso, head of the Italian General Confederation of Labour (CGIL), led a protest march in the northern city of Turin, headquarters of the Fiat automaker and symbolic of Italy's shrinking industrial might. Camusso said change needs to be made "with, and not against the people," and that the government should heed the voices of the protesters.
The general strike created a patchwork of chaos as local transport, schools, ports and other services were shut down on rotating schedules.
Unions are protesting Renzi’s Jobs Act, passed by the Senate on Dec. 3. It's designed to overhaul the country’s labour market, and make the hiring and firing workers easier.
With unemployment at record levels and youth jobless rates topping 40 per cent, unions say the burden of the reforms and spending cuts is being placed unfairly on workers and will do nothing to revive growth.
The Jobs Act is part of a package of promised measures to revive the eurozone's most sluggish economy, whose citizens had less spending power on average in 2013 than they had at the start of the century.