Barclays alerted US regulators as far back as 2007 to concerns that banks were rigging benchmark interest rates, according to documents released yesterday, but policymakers on both sides of the Atlantic did not appear to take decisive action, underscoring the chaos of the financial crisis.

The Federal Reserve Bank of New York was pushed to release the documents amid a furor that was touched off when Barclays late last month agreed to pay $453 million in fines for attempting to manipulate Libor.

Libor, or the London interbank offered rate, is calculated daily in London when panels of banks submit estimates of how much it costs them to borrow.

It is a major index that helps judge the health of banks and influences rates on all kinds of loans.