The euro fell on Thursday below $1.10 for the first time since 2003 and the U.S. dollar added to gains against an index of currencies after the European Central Bank said it will next week launch a massive bond-buying program meant to boost economic growth.

The euro zone common currency, which has lost about 15 percent against the dollar in six months, briefly traded under $1.10 for the first time since September 2003 and hit a session low of $1.0988.