The sharp words from Foreign Minister Sigmar Gabriel came after Trump concluded his first official tour abroad which took him to Saudi Arabia, Israel, Brussels and then Italy for a G7 summit.
They followed Chancellor Angela Merkel's warning on Sunday that the United States and Britain may no longer be completely reliable partners.
Germany's exasperation was laid bare after the G7 summit which wrapped up on Saturday with the US refusing so far to sign up to upholding the 2015 Paris climate accord.
Gabriel said today that "anyone who accelerates climate change by weakening environmental protection, who sells more weapons in conflict zones and who does not want to politically resolve religious conflicts is putting peace in Europe at risk".
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"The short-sighted policies of the American government stand against the interests of the European Union," he said, judging that "the West has become smaller, at least it has become weaker".
Germany's harsh words for Washington, traditionally a close ally, were highly unusual and came as relations have grown increasingly frosty.
When Trump was inaugurated in January, Merkel had told the billionaire and former reality TV show star that cooperation would be on the basis of shared democratic values.
The relationship between Merkel and Trump contrasts with the warm ties between her and former US president Barack Obama -- who last week travelled to Berlin to attend a key Protestant conference.
At the alliance's meeting on Thursday, Trump lambasted 23 of the alliance's 28 members -- including Germany -- for "still not paying what they should be paying" towards the funding of the bloc.
After the NATO and G7 summits, Merkel said at an election rally in southern Germany that "the times in which we could completely depend on others are on the way out. I've experienced that in the last few days.