Hundreds of rioters looted shops in Athens today after a mass anti-government rally against new government cuts erupted into violence.
Outside parliament demonstrators hurled lumps of marble and petrol bombs at riot police, who responded with tear gas and stun grenades. Police said at least 14 officers were taken to hospital.
The violence spread across the city centre, as at least 100,000 people marched through the Greek capital on the first day of a two-day general strike that unions described as the largest protest in years.
Police and rioters held running battles as thick black smoke from burning rubbish and bus-stops set ablaze filled the city's skyline.
The strike, which grounded flights, disrupted public transport and shut down shops and schools, came ahead of a parliamentary vote Thursday on new tax increases and spending cuts.
International creditors have demanded the reforms before they give Greece its next infusion of cash. Greece says it will run out of money in a month without it.
Most of the protesters who converged in Athens marched peacefully, but crowds outside parliament clashed with police who tried to disperse them with repeated rounds of tear gas. A petrol bomb set fire to a presidential guard sentry post at the Tomb of the Unknown Soldier, while running clashes broke out in several side streets near the legislature and the capital's main Syntagma Square.
Nearby, groups of hooded, masked protesters tore chunks of marble off building fronts with hammers and crowbars and smashed windows and bank signs. Scuffles also broke out among rioters and demonstrators trying to prevent youths from destroying storefronts and banks along the march route.
Vendors sold swimming goggles to rioters, who used them to ward off the tear gas.
Thousands of people watched the skirmishes, some standing on kiosk roofs to get a better view.
In Greece's second city of Thessaloniki, protesters smashed the facades of about 10 shops that defied the strike and remained open, as well as five banks and cash machines. Police fired tear gas and threw stun grenades.
All sectors - from dentists, hospital doctors and lawyers to shop owners, tax office workers, pharmacists, teachers and dock workers - walked out.
Flights were grounded in the morning but some resumed at noon after air traffic controllers scaled back their strike plan from 48 hours to 12. Dozens of domestic and international flights were still cancelled. Ferries remained tied up in port, while public transport workers staged work stoppages but kept buses, trolleys and the Athens metro running to help protesters.
In Parliament, Finance Minister Evangelos Venizelos said Greeks had no choice but to accept the hardship.
"We have to explain to all these indignant people who see their lives changing that what the country is experiencing is not the worst stage of the crisis," he said. "It is an anguished and necessary effort to avoid the ultimate, deepest and harshest level of the crisis. The difference between a difficult situation and a catastrophe is immense."
Demonstrations during a similar 48-hour strike in June left the centre of Athens convulsed by violence as rioters clashed with police on both days while parliament voted on another austerity package.
Most stores in the city centre, including bakeries and kiosks were shut. Several owners said they had received threats that their businesses would be smashed if they attempted to open.
The measures to be voted on come after more than a year and a half of repeated spending cuts and tax increases. They include new tax hikes, further pension and salary cuts, the suspension on reduced pay of 30,000 public servants and the suspension of collective labour contracts.