Uncertainty regarding the result of this month's Scottish independence referendum has weighed on the British pound.
The euro sagged on Tuesday to fresh one-year lows against the dollar on bets the ECB will do more to help a wobbly euro zone economy.
The euro hit a year-low against the dollar on Monday, as investors added to bets against the single currency before a policy meeting this week.
The dollar rose on Friday, with traders looking beyond soft U.S. consumer-spending data.
Better-than-expected U.S. growth data lifted the dollar on Thursday as the euro fell amid worries about tensions between Ukraine and Russia.
The euro turned higher in choppy trading Wednesday as traders reacted to headlines that the ECB is unlikely to take new action early next week.
The dollar softened on Tuesday while the euro further struggled on expectations of soft inflation data and more monetary easing.
One analyst has warned of a crowded trade in the euro currency that could spell pain for some investors if not treated with caution.
The euro fell to its lowest in nearly a year against a broadly firmer dollar on Monday after comments from the head of the European Central Bank.
Yellen's speech cited persistent labor market slack but noted faster recovery in the sector could accelerate the timing of a Fed interest rate hike.
Central bankers gathered for a three-day meeting in Wyoming that will feature a potentially market-rattling speech by Fed Chair Janet Yellen.
The euro recovered from a 11-month low against the dollar, helped by better-than-expected German private sector growth data.
U.S. housing starts surged past expectations in July, snapping two straight months of declines.
The US dollar rose against a basket of major currencies on Monday on reduced concerns over Russia and Ukraine and positive US housing data.
The dollar failed to get a safe-haven boost despite news that the Ukraine-Russia conflict had entered a potentially dangerous phase.
A robust U.S. 30-year bond auction supported Treasuries prices in general and weighed on yields, which has underpinned the greenback, analysts said.
The British pound also falls on inflation, wages data, and the yen is subdued after Japan's Q2 GDP contraction.
The euro fell towards 9-month lows against the dollar on Tuesday, as investors positioned for a weak German sentiment survey.
The Norwegian crown hit a seven-week high against the euro after Norway reported consumer inflation unexpectedly jumped in July.
The euro gained against the dollar and sterling, and investors flocked to the Swiss Franc and yen as Obama approved air strikes in Iraq.