BRUSSELS/FRANKFURT (Reuters) - The European Union’s antitrust authority has charged eight unnamed banks with operating a cartel in trading euro zone government bonds between 2007 and 2012, years when the financial crisis dragged down banks and countries.

The European Commission said in a statement that some traders at the banks exchanged commercially sensitive information and coordinated trading strategies on the euro-denominated bonds, mainly through online chatrooms.

The move by the European Commission’s powerful antitrust arm is the latest blow to the public image of Europe’s banks, which have paid out billions of euros in fines, including for rigging interest rate benchmarks used to price home loans.

The Commission said that its charges did not imply that anti-competitive conduct was a general practice in the euro zone government bond sector.

In a separate, earlier case, the Commission charged Deutsche Bank, Credit Agricole, Credit Suisse and a fourth bank in December with being part of a bond cartel, also citing traders using chatrooms.

If found guilty of breaching EU antitrust rules, the banks could face fines up to 10 percent of their global turnover.

The EU’s executive has imposed hefty fines in the past, including a record $5 billion penalty on Google for competition abuse last year.

In 2013, the authority imposed a 1.5 billion euro penalty on banks, who were involved in cartels on financial derivatives.

“The Commission has concerns that, at different periods between 2007 and 2012, the eight banks participated in a collusive scheme that aimed at distorting competition when acquiring and trading European government bonds,” it said.

“Traders employed by the banks exchanged commercially sensitive information and coordinated on trading strategies. These contacts would have taken place mainly - but not exclusively - through online chatrooms.”