BUSINESS STRATEGY – ATHENS — Swarms of violent groups overtook a general protest against austerity measures in the city center on Wednesday, lashing out at the government and security forces and hurling gasoline bombs that, according to the police, set fire to a bank building and killed three workers.

The demonstration had drawn tens of thousands of people near the central square in front of Parliament as part of a general strike that paralyzed airline flights, ferries, schools and hospitals. It did not initially appear different from many other, mostly peaceful protests in recent months, as Greece’s financial crisis has deepened and the likelihood of painful sacrifices has grown into a certainty.

But among the demonstrators were subgroups of protesters who numbered in the hundreds — mostly young and many clad in black, wearing hoods or masks and carrying helmets, wooden bats or hammers — and whom the police and other demonstrators identified broadly as anarchists. They led efforts to storm the Parliament building, chanting “thieves, thieves,” and hurling rocks and gasoline bombs. Some chased the ceremonial guards from the Tomb of the Unknown Soldier in front of the building.

The police responded with tear gas canisters that spread a choking pall over the crowd.

In midafternoon, in a nearby neighborhood, a firebomb was flung into the Marfin Egnatia Bank, trapping at least 20 people. Firefighters worked to evacuate them, but the police said a man and two women stranded on the second floor died from smoke inhalation. Colleagues sobbed in the street.

The deaths shocked many in Greece, where demonstrations have been a way of life for decades and played a pivotal role in the overthrow of military rule in 1974. In December 2008, thousands of rioters across Greece clashed with security forces for weeks over the fatal shooting by the police of a 15-year-old boy, without any further deaths. Read more »