The U.S. dollar traded about 0.8 percent higher against major world currencies, with the euro near $1.08, touching its lowest level since August. The yen traded near 121.57 yen against the greenback.
In the afternoon, New York Fed President William Dudley told reporters that he would "completely agree" with Yellen's remarks that December is still a possibility, Reuters said. His speech on looking beyond the macro economy did not discuss the current state of U.S. monetary policy.
Fed Vice Chair Stanley Fischer speaks at 7:30 p.m. on central bank independence at the National Economists Club.
"This is the crescendo of Fed speakers. You have Dudley, Fischer and Yellen, and I think all of that helps because it coalesces around (raising rates in) December," said Art Hogan, chief market strategist at Wunderlich Securities.
Before the open, Fed Gov. Lael Brainard spoke in Frankfurt, saying the Fed is "very dependent" on incoming data, but that there have been some tightening of economic conditions.
Philadelphia Fed President Patrick Harker did not comment on the U.S. economy and monetary policy in prepared remarks for a speech on social innovation capital, Reuters reported.
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Economic data gave a somewhat mixed view on the services sector, which remains well in expansion territory. The non-manufacturing ISM October report showed a rise to 59.1 from 56.9 the prior month. However, Markit said its October PMI services index declined to 54.8 from 55.1 in September.
With two days to Friday's nonfarm payrolls report, the ADP employment report showed private companies added 182,000 jobs in October.
September's trade deficit came in at $40.8 billion, its lowest level in seven months, Reuters reported.
In other economic news, weekly mortgage applications fell 0.8 percent last week as interest rates rose.
Stock index futures held higher after the data releases, with the Dow futures up about 40 points.
European stocks closed mixed, with Volkswagen weighing on the DAX but the STOXX Europe 600 up about half a percent.
Glencore gained more than 5 percent in London trade after the firm said it was on track to reduce its debt thanks to asset sales and was making deeper cuts in copper output to support weak prices, Reuters reported.