He said several ECB policymakers at a meeting on Thursday had questioned a change in U.S. policy.

U.S. Treasury Secretary Steve Mnuchin said this week he welcomed a weak dollar, arguing that it was good for U.S. trade, and Commerce Secretary Wilbur Ross said "U.S. troops are now coming to the ramparts" in global trade wars.

Without being specific, Draghi said the euro had risen partly because of "the use of language in discussing exchange rate developments that doesn't reflect the terms of reference that have been agreed".

That was a reference to last October's International Monetary Fund meeting in Washington where countries had agreed they would "refrain from competitive devaluations and ... not target our exchange rates for competitive purposes".

"Several (ECB Governing Council) members expressed concern, and this concern was in a sense broader than simply the exchange rate, it was about the overall status of international relations right now...

"If all this were to lead to an unwanted tightening of our monetary policy ... then we will have to just think about our monetary policy strategy," Draghi said.

The euro is at a three-year high against the dollar.

(Reporting by Jeremy Gaunt; Editing by Catherine Evans)