The Russian central bank said it was prepared to support the ruble in foreign exchange markets after it tumbled to new lows on Friday.
The euro plunged to its lowest in more than two years against the dollar on Thursday.
The dollar nursed modest losses on Wednesday as investors took some profits on a four-session rally that swept the greenback to multi-year highs.
The euro rallied on Tuesday on a report citing internal tensions within the European Central Bank over the leadership of its chief, Mario Draghi.
The dollar topped 114 yen on Monday, its highest level in nearly seven years, extending gains spurred by the Bank of Japan's decision last week.
The yen tumbled to its lowest level in nearly seven years against the dollar, putting it on track for its biggest losses in 18 months.
The dollar extended recent gains to a 3-1/2-week high, boosted by strong third-quarter growth and a newly hawkish tone from the Federal Reserve.
The dollar steadied as investors awaited guidance from the U.S. Federal Reserve, expected to reiterate caution on raising interest rates.
The dollar fell on Tuesday on disappointing U.S. durable goods and home price data ahead of a Federal Reserve policy meeting.
The euro recovered lost ground in rangebound trade on Monday, boosted by weaker-than-expected U.S. housing data.
The euro rallied on Friday ahead of an official report on the health of the euro zone's main banks as investors covered short-positions.
The dollar rallied on Thursday as investors plowed cash back into riskier asset classes, with an underpinning of promising data.
The US dollar extended broad-based gains on Wednesday after slightly higher-than-expected US inflation data and amid concerns over European banks.
The euro fell sharply against the dollar on Tuesday after Reuters reported the European Central Bank was looking at buying corporate bonds.
Sameer Samana, Wells Fargo Advisors, and Kathy Lien, BK Asset Management, discuss what's driving oil prices lower as global demand continues to grow amid a stronger U.S. dollar.
Major currencies traded in tight ranges on Monday with investors facing a vacuum of data and modest price changes in global markets.
The U.S. dollar edged higher against a basket of major currencies on Friday after strong data on U.S. consumer sentiment calmed nerves.
The U.S. dollar recovered against a basket of major currencies on Thursday on the view that Wednesday's selloff was overdone.
The U.S. dollar hit a three-week low against the euro and a more than one-month low against the yen on Wednesday.
The U.S. dollar recovered against a basket of major currencies on Tuesday after worrying economic data came out of the euro zone and United Kingdom.