"There is a certain worry or concern about the state of global relations, because if you put tariffs against what are your allies, one wonders who the enemies are", said Draghi.
'If the outlook becomes less favourable... the Governing Council stands ready to increase the asset purchase programme (APP) in terms of size and/or duration'.
US stocks edged higher as investors awaited details of President Donald Trump's tariff plan and set their sights on Friday's jobs report.
The resignation of Cohen has been seen as a sign that the White House intends to follow through with the imposition of its tariffs on steel and aluminum, despite nearly universal opposition from trading partners and indeed Republicans in Congress.
Draghi said the most important aspect of any potential tariffs would be the impact on economic confidence, which is "difficult to assess". The bloc's economic growth did not gain positive momentum in the fourth quarter of 2017 either as final readings indicated yesterday.
At Thursday's meeting, policy makers unanimously chose to change their guidance, though they kept an option to extend the program further after September, when bond buying is now scheduled to expire.
'They toned down the easing bias but there is still a willingness to ease and the tone of Draghi's comments was still dovish, stressing that there is still not a convincing uptrend in inflation. Regarding the Latvian banking scandal, Draghi said the ECB did not have enough information on the matter and was sending a letter to the European Court of Justice seeking a clarification on whether the detention of the central bank governor Ilmar Rimsevics were in compliance to the ESCB statute.
While the central bank will continue its monthly bond purchases of €30 billion through at least September, it removed language that indicated the bank would step up with more quantitative easing (QE) if necessary. Draghi's shift nevertheless acknowledges that the ECB's emergency stimulus will have to end in the not-so-distant future. It could cause the euro to rise in value against other currencies, potentially hurting exporters, and it could bring higher returns on savings as well as stiffer borrowing costs for indebted governments in the 19-country eurozone. The fund targets companies that are now members of MSCI Europe and have increased dividend payments each year for at least 10 years and are thus stable in nature.
This week has seen sharp swings in stocks from positive to negative as predictions the measures will not be as bad as feared were offset by news Wednesday the president's pro-trade top economics advisor Gary Cohn had resigned.
It is hoped that this in turn will propel the US unemployment rate to strike a new 17-year low of 4%, likely helping to strengthen the US Dollar. But while growth has bounced back, inflation has been slow to respond.
Inflation, at 1.2 per cent, remains well below the ECB's target of just below 2 per cent.
The bond-purchase stimulus has been pumping newly created money into the eurozone economy since March, 2015.