Greek police clash with protesters

Protesters chanted slogans against unpopular austerity measures and held up banners reading "Social Revolution Now" as they marched to parliament, where a vote on the 2012 budget was expected later in the evening.

The teenager's killing three years ago sparked the country's worst riots in decades. They were fuelled by anger over economic hardship and helped topple the then conservative government.

Turnout was lower at Tuesday's march compared to similar protests in previous years, but quickly turned violent as youths dressed in black pelted police with pieces of broken pavement, wooden sticks and petrol bombs.

At least 10 people were slightly injured, Reuters witnesses said. Small groups of protesters set garbage containers on fire and smashed some shop and bank windows in central Athens.

The crowd was dispersed by police in less than an hour but another, bigger march was planned for 4 p.m. British time.

Since the country's debt crisis erupted in 2009, austerity-hit Greeks have repeatedly staged protests that often turn violent.

Minor clashes erupted between demonstrators and police in other parts of Athens and in the northern city of Thessaloniki.

In 2008, thousands battled police for weeks after 15-year- old Alexandros Grigoropoulos was shot dead. They trashed shops, attacked public buildings and burned cars, making central Athens look like a war zone for weeks.

(Reporting by Renee Maltezou; Editing by Robert Woodward)