Philadelphia Fed President Charles Plosser said Tuesday he was concerned the Fed's balance sheet has grown "quite a lot" and cautioned monetary policy was not a precise tool for manipulating employment levels. In answer to questions from the audience at an event in San Diego, Plosser said it was important to preserve the independence of the central bank. Earlier, Plosser said the United States does not want to find itself in the same place as the United Kingdom, where the country has had elevated inflation for over three years, and he said the Fed may need to scale back the level of monetary-policy support "well before the end of 2014." Plosser was expected to take questions from reporters later Tuesday.

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