By Anna Willard

WASHINGTON, April 25 (Reuters) - The EU could ignore the International Accounting Standards board and set its own rules if the body does not respond quickly to a U.S. easing in fair-value accounting, a European Central Bank official said on Saturday.

The IASB, which sets mandatory accounting rules used in the European Union, on Friday ignored pleas from EU officials to loosen the rules. It said its guidance was already in line with changes announced this month by its U.S. counterpart the Financial Accounting Standards Board (FASB).

EU officials fear that if the IASB makes no immediate changes, banks in the 27-country bloc would be at a disadvantage to their U.S. peers and demanded a speedy response at a meeting earlier this month.

"What we can do is that Europe can very well reclaim its freedom," said ECB governing council member Christian Noyer at a press conference on the sidelines of the spring meetings of the IMF and World Bank.

"It's not the IASB that makes the law in Europe. If we decide to take back control and write the accounting rules in the European directive ourselves without following the IASB, the issue would be resolved. So it's very simple."

Fair value measures assets on company balance sheets by their market worth.

"A level playing field exists in this area," the IASB said in a statement after a two-day board meeting.

French Economy Minister Christine Lagarde said she was very concerned about the IASB decision.