"Prospects for labour markets will continue to improve, and I expect the unemployment rate will continue to decline, reaching 6.2 per cent or lower by the end of 2014," Plosser said in a statement of his talk at the Official Monetary and Financial Institutions Forum in London, the UK.
"On monetary policy, we must back away from increasing the degree of policy accommodation in a manner commensurate with an improving economy," Plosser said. "Reducing the pace of asset purchases in measured steps is moving in the right direction, but the pace may leave us well behind the curve if the economy continues to play out according to the FOMC forecasts."
In afternoon trading in New York, the Dow Jones Industrial Average rose 0.52 per cent, the Standard & Poor's 500 Index gained 0.37 per cent, while the Nasdaq Composite Index advanced 0.17 per cent. Earlier the S&P 500 climbed to a record high 1,881.94.
Shares of Caterpillar and JPMorgan Chase gained, last up 1.8 per cent and 1.2 per cent respectively, leading the increase in the Dow.
So far in 2014, the S&P 500 has added 2.2 per cent, while the Nasdaq has risen 4.8 per cent. The Dow has lost 0.3 per cent in the same period.
In Europe, the Stoxx 600 Index edged higher to close at 337.28. The gauge, which has fallen 0.2 per cent so far this week amid tension over Ukraine, is 0.3 per cent away from a six-year high reached February 25, according to Bloomberg News.
The UK's FTSE 100 rose 0.2 per cent, while France's CAC 40 added 0.6 per cent. German's DAX finished the session little changed from the previous close.
The European Central Bank maintained its benchmark interest rate at a record low 0.25 per cent, as had been expected by most economists and forecast a gradual increase in inflation.
"The news that has come out since the last monetary policy meeting are by and large on the positive side," ECB President Mario Draghi told reporters in Frankfurt on Thursday, according to Bloomberg. He said while there were political risks to what was happening in Ukraine, it was too early to say, except for Russia, what the global economic impact would be.
Meanwhile the Bank of England kept its key rate at 0.5 per cent and its bond-buying plan at 375 billion pounds.