Violence flares as demonstrations against economic crisis spread around the globe

Confrontation and violence marked street demonstrations against the economic crisis across the globe yesterday, as showdowns between police and protesters flared in Italy, Greece and the US, while London's demonstrators prepared for battle in the courts.

Italian students armed themselves with firecrackers, rocks, eggs and smoke bombs as widespread disturbances broke out across the country. Police in Milan used pepper spray to counter protests against the "bankers' government" of the new Prime Minister Mario Monti, while anarchists clashed with officers in Turin, authorities charged students in Palermo, and Bari and Rome saw their own demonstrations.

Fire bombs and tear gas left clouds hanging above Athens last night, after between 20,000 and 50,000 protesters marched through the Greek capital only to come up against 7,000 police officers. In a country where street clashes sparked by rage at government austerity measures have become commonplace this year, yesterday's march was even more angry than usual due to the anniversary of the Athens Polytechnic uprising, when Greece's military junta sent in troops to put down a student demonstration in 1973.

There were 60 arrests, but no injuries were reported despite the police's use of stun grenades.

In London, by contrast, the 6pm deadline for the demonstrators and their tents to leave the square outside St Paul's passed relatively quietly. Leaders of the occupation said nobody had left, and two lawyers acting for the camp announced a case against the Corporation of London's eviction notice would be heard by the High Court.

In New York , however, Occupy Wall Street protesters clashed with police after they tried but failed to take over the streets around the Stock Exchange in Manhattan. Disturbances on the two-month anniversary of the movement also broke out in other American cities.

Police said that roughly 75 people had been in arrested during the morning in Manhattan. After most of the protesters were repelled from the area around Wall Street, about a thousand of them marched back to Zuccotti Park, the public plaza that became the focal point for the movement before it spread rapidly to cities across the US.

In Los Angeles hundreds of protesters and union members marched through the financial district shouting: "Whose streets? Our streets". And in Dallas more than a dozen people were arrested after police broke up an encampment near City Hall.

Most of the arrests in New York came when marchers tore down metal barriers set up to ensure they entered Zuccotti Park in single file. The protest was expected to grow last night, with plans to occupy subway stations and to hold a rally outside City Hall and a march across Brooklyn Bridge.