The dollar rose sharply on Wednesday as remarks from Federal Reserve Chair Janet Yellen intensified bets the central bank would raise interest rates next month if the overall economy improves further.

The dollar index added to earlier gains tied to surprisingly upbeat data on the U.S. services sector, propelling this measure of the greenback against a basket of currencies to 3-month highs. The dollar index was up 0.8 percent at 97.94.