European Union lawmakers called for tougher dealings with the United States over financial rules as key regulatory deadlines slip, but the bloc's top market watchdog said such tactics would backfire.
The lawmakers worry the United States is stalling on introducing global standards for how much cash banks must set aside to cover risk on their books.
The so-called Basel II rules will be introduced a year earlier in Europe than in the United States, a gap that EU Internal Market Commissioner Charlie McCreevy said would incur extra costs for EU banks operating in America.
There have also been delays on the US side in recognising each other's accounting standards, lawmakers said.
Members of the European Parliament's economic affairs committee also said a new Democratic Congress could lead to a bout of US protectionism.
Jonathan Evans, a British conservative lawmaker, said two US stock markets, Nasdaq and NYSE, were able to bid for European bourses, but many doubt Congress would allow the reverse to happen.
And the committee's chairman, French socialist Pervenche Beres, told McCreevy of a need to bring to the transatlantic regulatory dialogue "a much stronger voice than you seem to be doing".
"Maybe we need to be a little bit more hardball with the Americans. Maybe they need to walk the walk and talk the talk," added John Purvis, a British conservative.
The lawmakers were disappointed that attempts to create an all-European bourse champion had failed. NYSE's planned take-over of pan-European bourse Euronext and Nasdaq's bid for the London Stock Exchange showed the EU had the right regulatory approach, he said.
It was important that exchanges in the EU followed the bloc's rules, McCreevy said.