CNN's Ben Wedeman said the government must strike a fine balance between sometime violent domestic oppostion and its international debt obligations. "In elections next year we'll see how successful the government was in achieving this balance."
In Greece, police said 5,000 people took to the streets to protest peacefully over the economic pain they are suffering. In the last two years alone public sector workers have seen their wages shrink by up to 40%.
Unemployed civil servant Evangelia Katsaropoulou explained why she planned to join the protests. "I have two children, they're twins, and the situation is tragic," she told CNN.
"What I want to say to everyone is that they have to come onto the streets and shout so that these measures do not take place."
The International Monetary Fund and the European Union are debating whether and when Greece can receive its next bailout payment.
Protesters, such as pensioner Thimios Marvitsas, hope to remind them that they are the ones bearing the burden of austerity. "All these measures they are pushing us back 50, 60 years," he said.
"They are cutting our pensions in half, there is a million unemployed, more taxes. In other words our lives are just getting worse and worse."
Even in Germany there were protests, including 200 demonstrators in Berlin. CNN's Fred Pleitgen said that unions organized the protests more out of solidarity than real anger. However he added that the economy was slowing down and the eurozone crisis was taking its toll on the labor market. Unemployment is lower than in other countries but trades unions warn that austerity measures could damage the economy.
"Angela Merkel has become a lightning rod for protesters across Europe due to anger over her insistence that debt-ridden countries adopt austerity," he said. "Now the same is happening in Germany itself."
In Belgium, about 200 people protested, but no violence was reported, police said.