NEW YORK—The Federal Reserve Bank of New York said documents released Friday showed its officials were concerned about the veracity of the London interbank offered rate in late 2007.

According to the documents, New York Fed officials met in April and May of 2008 to figure out what they could do to address problems with Libor. The release was comprised of emails and telephone transcripts. The documents also show Barclays PLC acknowledging that it was lowballing its borrowing-cost estimates as of the spring of 2008.

The...