In Italy shares were down almost 4%, in France the Cac index fell 2.7%, Germany's Dax fell 2.3%, and London's FTSE 100 was down 1%.
Banks across Europe were hit hard, with Italy's Unicredit down 6.3%.
Eurozone finance ministers were holding talks on a new aid plan for Greece, but this was overshadowed by fears of contagion spreading to Italy and Spain.
The euro fell, while borrowing costs for Spain and Italy rose to a 12-year euro-era high.
"There are tensions across the eurozone, we must find a solution," Belgian minister Didier Reynders said to reporters on arrival at the finance ministers' meeting.
Ministers are discussing how, and by how much, banks and other financial institutions can contribute to a new rescue package for Greece.
Spanish Prime Minister Jose Luis Rodriguez Zapatero called for a "swift and precise clarification" of how a second bail-out for Greece might work.
German Chancellor Angela Merkel also urged speedy action on new aid for Greece, and added that Italy needs to send a "very important signal" by passing an austerity budget.
Italy's Finance Minister Giulio Tremonti has proposed 48bn euros ($67bn; £42bn) in budget cuts over three years and aims to cut the deficit to zero by 2014 from this year's 3.9% of gross domestic product.
However, financial markets were unsettled by remarks from Prime Minister Silvio Berlusconi, who indicated in a newspaper interview that the austerity plan might not have full cabinet support.
In a sign that investors are growing more risk averse, the yield on Italian 10-year bonds jumped to 5.6% from 5.3%. Meanwhile, yields on Spanish 10-year bonds rose to 5.9% from 5.7%.
Source: http://www.bbc.co.uk/news/business-14113796