New waves of Greek workers walked off their jobs Thursday in a heightened protest of the government’s effort to impose austerity measures to satisfy international creditors.

Public transportation ground to a halt in Athens, while power company workers sought to block their employer from collecting a new property tax and lawyers refused to appear in court. The electric workers said the power company should not be used as a tax collector, with customers threatened with a power cutoff if they don’t pay the tax.

The protests in Greece came as European officials voiced new worries about the effects of the continent’s governmental debt crisis. It has roiled international stock markets for weeks, with share values falling again Thursday on London, Paris and Frankfurt exchanges.

The French finance ministry said banks heavily exposed to Greek debt might have to take losses of more than the 21 percent that was proposed in a July agreement calling for a second bailout for the Athens government. Some officials are suggesting that the banks’ losses on Greek securities could reach 50 percent.

European financial officials have been pressing banks to increase their cash reserves so that they can withstand possible losses on government bonds they bought from Greece and other debt-ridden countries. But one major lender, Germany’s Deutsche Bank, balked at that idea Thursday. The bank said it is the responsibility of governments to restore stability in their finances.

In Slovakia, lawmakers continued to shape an agreement to approve expansion of the bailout fund for the eurozone, the 17-nation bloc that uses the common euro currency. The Slovak Parliament rejected the expanded bailout earlier this week, toppling the government of Prime Minister Iveta Radicova.

The political opposition has agreed to approve Slovak financial support for the $596 billion fund in a new vote later Thursday or Friday, in exchange for a new general election next March.

The Greek protests are part of a string of demonstrations against the government-imposed austerity measures. The Greek Parliament is set to vote next week on the latest plan, one that would sharply cut the pay for 30,000 civil servants and eventually eliminate their jobs.