Eighteen Greek electricity workers will be charged on Monday with breaching the peace after police broke up an anti-austerity protest ahead of a visit by German Chancellor Angela Merkel.
Those to appear before a prosecutor include Nikos Fotopoulos, the leader of Greece's powerful GENOP union, which has promised rolling 48-hour power strikes when a new round of austerity measures is put before parliament.
Riot police moved in late on Sunday after workers occupied a data centre of utility PPC to protest against a deeply unpopular property tax collected through electricity bills that was imposed last year to shore up the country's finances.
"You've turned our life into hell and the country into a protectorate," the union said in a statement on Sunday announcing the occupation of the facility.
Greek Prime Minister Antonis Samaras promised on Thursday to maintain law and order after unpaid dock workers tried to storm the defence ministry. "I will not allow this country to become defenceless," he told reporters.
Discontent with EU/IMF-imposed budget and wage cuts is rising in Greece. Merkel is due to visit Athens on Tuesday in an intended show of support for the austerity policies pursued by Samaras' fragile three-party ruling coalition.
But she faces a hostile reception from a people worn down by years of recession, with demonstrations planned in the Greek capital. Many Greeks blame Merkel and the austerity policies she is backing across Europe for their plight.
The Greek economy has shrunk by about a fifth since 2008, partly due to austerity measures demanded in exchange for the bailouts. Unemployment in the private sector is at a record 24 percent. State workers have lost about a third of their income.