The European and Japanese central banks are singing similar - and repetitive - policy tunes while facing the same challenges: the best economic growth in years but no sign of rising inflation, and doggedly strong currencies keeping a lid on prices.
The ECB added that monthly net asset purchases of €30 billion were meant to run until the end of September, or beyond, if necessary.
That prompted the euro to give up the gains it posted after the ECB's post-meeting statement, while the lack of any signals of broader changes to the policy stance also pushed bond yields in Germany and France off two-week highs.
For its part, the Bank of Japan, which abandoned setting short-term interest rates altogether, is also keeping steady asset purchases that have been in place in various forms for most of almost 20 years and have greatly intensified recently.
A majority of economists in a Reuters poll taken last week said the peak of growth momentum in the euro zone was now in the rear-view mirror.
Indeed, since the beginning of 2017 - and three quarter-point rate hikes from the Fed - the dollar has lost more than 12% on a trade weighted basis.
Trump is expected to announce his tariff decision by the end of this week.
"While we certainly don't want to become bearish on the growth outlook, recent data seem to suggest that the acceleration in growth might soon start to level off", Peter Vanden Houte wrote in ING's latest global outlook. They could depress confidence among consumers and businesses, he said, which could weaken both growth and inflation.
Fears of a transatlantic trade war and political deadlock in Italy did not deter policymakers from the strong hint that the end of their support for the 19-nation single currency area is drawing closer.
While ECB inflation projections have consumer prices hovering around the 1.5% inflation rate by the end of 2018 and rising gradually over the medium term, Draghi told reporters that underlying inflation measures will remain subdued - so "victory can not be declared yet".
"Given the risks around global trade as a result of U.S. imposed tariffs and some extra political risk in Italy, it is unlikely that the European Central Bank will move any faster than markets expect anytime soon, particularly given inflation remains subdued well below their targets", Robbins said.
The Governing Council kept interest rates unchanged, as expected: the benchmark main refinancing rate at zero and the deposit rate at minus 0.40 per cent. Against the pound, the euro was 0.13% lower at £0.8916 and fell 0.65% to Y130.81 versus Japan's yen.
Attention now turns to ECB President Mario Draghi's 1330 GMT news conference, where he will unveil fresh macroeconomic projections and face questions about the euro's rise and market volatility.
The Stoxx Europe 600 index climbed 1.1% to 376.62, the best close since February 28, FactSet data showed.