WASHINGTON – The Federal Reserve Bank of New York released documents Friday that show it learned five years ago of big banks understating their borrowing costs to manipulate a key interest rate.

The documents also show Treasury Secretary Timothy Geithner, who was then president of the New York Fed, urged the Bank of England to make the rate-setting process more transparent.

A congressional panel requested the documents and is investigating manipulation of the London interbank offered rate (LIBOR) rate, which affects what people pay for loans.