The euro fell as low as $1.41612, according to the EBS trading platform. It was last at $1.41840, down 0.7 percent on the day.
Traders said the ECB bought Spanish and Italian debt early in the European session after it said on Sunday it would "actively implement" its bond-buying program.
Market participants are bracing for volatility ahead of the open of the New York Stock Exchange in the first session after Standard & Poor's downgraded US debt.
Copyright Reuters, 2011