St. Louis Fed President James Bullard said in a speech on Thursday that the Fed should start raising its interest rate as the Fed's targets are reached.

"During 2015, I have been an advocate of beginning to normalize the policy rate in the U.S. My arguments have focused on the idea that the U.S. economy is quite close to normal today based on an unemployment rate of 5 percent, which is essentially at the Committee's estimate of the long‐run rate, and inflation net of the 2014 oil price shock only slightly below the Committee's target," he said.

"My current policy views have not changed," Bullard added.

He pointed out that the Fed's monetary policy should be changed if interest rate and inflation will remain low.

"Should we find ourselves in a persistent state of low nominal interest rates and low inflation, some of our fundamental assumptions about how U.S. monetary policy works may have to be altered," St. Louis Fed president noted.