The Federal Reserve will need to begin raising rates well before unemployment falls to its long-term "natural" rate of 5.5 percent, but will look at a much broader range of economic data before making its decision, a top Fed official said on Tuesday.

At the time the Fed will need to exit its current policy of near-zero interest rates, the unemployment rate will be around 7 percent, San Francisco Fed President John Williams told reporters after a speech at the University of San Diego School of Business Administration. That's likely to happen at the end of 2014, he said.

But that doesn't mean he views a drop to 7 percent as a trigger for raising rates, he said. That view differentiates him from fellow policy dove Chicago Fed President Charles Evans, who has argued that the Fed should commit to keeping interest rates low until unemployment falls to below 7 percent, unless inflation threatens to rise above 3 percent.

"It's not just the unemployment rate, I'm looking at everything," Williams said.