In late New York trading on Monday, the euro rose to $1.1190 from $1.1185 of the previous session, and the British pound decreased to $1.3114 from $1.3127, Xinhua news agency reported.
The Australian dollar climbed to $0.7578 from $0.7554.
The dollar bought 101.94 Japanese yen, higher than 101.87 yen in the previous session. The dollar declined to 0.9777 Swiss francs from 0.9789 Swiss francs, and it inched up to 1.3013 Canadian dollars from 1.3006 Canadian dollars.
"In light of the continued solid performance of the labor market and our outlook for economic activity and inflation, I believe the case for an increase in the federal funds rate has strengthened in recent months," Yellen addressed central bankers at a conference in Jackson Hole, Wyoming, on Friday.
Pointing to solid growth in household spending and a strengthening job market, Yellen said the US economy is "now nearing" the Fed's statutory goals of maximum employment and price stability.
Analysts said it's possible for the Fed to hike interest rates as soon as September. But about 71 per cent of 62 economists surveyed by the Wall Street Journal this month believed the Fed will wait until December to raise rates.
The dollar index, which measures the greenback against six major currencies, was up 0.83 per cent at 95.562 in late trading on Friday, the highest level in three weeks.
The index inched down mildly on Monday and registered at 95.538 in late trading.
