The European Commission has fined a group of major global banks a total of 1.7 billion euros ($2.3 billion) for colluding to profit from the manipulation of key interest rates.

The banks, which include JP Morgan, Citigroup and HSBC, are accused of manipulating for years European and Japanese benchmark interest rates that affect hundreds of billions of dollars in contracts globally, from mortgages to credit card bills.

The Commission, the EU's executive arm, is only the latest to punish banks for profiting from manipulating interest rates, after similar cases brought by U.S. and national European market regulators.

"We want to send a clear message that we are determined to find and punish these cartels," competition commissioner Joaquin Almunia said Wednesday.

The banks named as participating in cartels were Barclays, Deutsche Bank, Royal Bank of Scotland, Societe Generale, Credit Agricole, HSBC, JPMorgan, UBS and Citigroup.

In a first cartel, which operated from 2005 to 2008 and was focused on euro-denominated derivatives, Deutsche Bank received the largest fine, of 468 million euros, followed by Societe Generale with 445 million euros. RBS was fined 131 million euros.

Barclays escaped a 690 million-euro fine because it was the bank that notified the Commission of the cartel's existence, while JPMorgan, HSBC and Credit Agricole have as yet not settled. JPMorgan and HSBC denied wrongdoing Wednesday, though JPMorgan settled with the Commission in a second cartel case.

"This is not the end of the story," Almunia said. He noted that further investigations are possible and the Commission is also probing a cartel it believes manipulated derivatives denominated in Swiss francs.

In a response to the fine, Deutsche Bank Chief Executive Juergen Fitschen referred to the euro cartel as a "legacy issue" caused by "past practices of individuals" at the bank. Fitschen has worked there since 1987 and became CEO in 2012.

He acknowledged participating in the cartel had been a "gross violation" of the bank's ethics. But he said the fine wouldn't hurt the bank's profits as it has already made provisions for the fines it deemed likely from regulators.

A second cartel fined by the Commission on Wednesday operated from 2007 to 2010 and focused on yen-based derivatives. The largest fines went to RBS and Deutsche Bank, 260 million euros each, while UBS received immunity from a staggering 2.5 billion-euro fine for revealing the existence of the cartel.

Societe Generale said its role was limited to a single trader who acted without knowledge of management. RBS, which has previously been fined by the U.S. and British authorities in rate-fixing cases, was more apologetic.

Chairman Philip Hampton said the bank's management became aware some of its employees had been helping fix rates in 2011 and has taken action to prevent it happening again. It has been keeping its team of interest rate traders separate from the rest of the company, monitoring its actions, and appointing a review board.

"The RBS board and new management team condemn the behavior of the individuals who were involved in these activities," Hampton said. "There is no place for it at RBS."