Chancellor Angela Merkel recalled her own youth in Soviet-dominated East Germany and said Germany was independent in its policy choices in a pointed response to Trump saying Berlin was a "totally controlled by Russia".
In front of television cameras, Trump continued to complain about Europe's lagging defense spending and castigated Germany for beginning construction on a second natural gas pipeline to Russian Federation. "They will be getting between 60 and 70% of their energy from Russian Federation and a new pipeline, and you tell me if that is appropriate because I think it's not", he continued.
"Because of me they've [NATO] raised about $40 billion over the previous year", the USA leader told journalists standing next to NATO Secretary General. On top of that, Germany is just paying a little bit over 1 per cent [on defence] ...
"I think it's very unfair to our country", Trump said.
A press aide demanded the media leave the room as Trump pushed Stoltenberg to explain how the U.S.is supposed to protect Germany when its opening the front door to Vladimir Putin. "So, I think that's inappropriate also". "It is very inappropriate".
Former secretary of state John Kerry blasted President Trump's criticism of Germany in a lengthy statement on Wednesday morning as "strange", "counterproductive", and "disgraceful".
Trump has raised the possibility of pulling US troops from Germany.
"We're having a great meeting", Mr. Trump told reporters.
Germany responded quickly to the criticism.
"Yes, we're anxious [about NATO], but on the other hand we start to realise how precious this alliance is", she added.
Even Stoltenberg - a mild-mannered former Norwegian prime minister who has cultivated a positive relationship with Trump - appeared reduced to spluttering as Trump cut him off after he started to explain that allies traded with Russian Federation even during the Cold War.
"We need a diversification of supplies, this is one of the most important goals of the European Union energy union", President Andrzej Duda told reporters at the summit. Other presidents has raised European defence spending levels in the past but he is intent on dealing with it.
"We are investing heavily in the German armed forces and other European countries too, because the armed forces need it". Trump exacerbated those fears ahead of the summit said he couldn't say whether Putin is a friend or foe and that their meeting "may be the easiest of them all".
U.S. ambassador to Nato Kay Bailey Hutchison urged allies to look beyond Trump's rhetoric and focus on the summit declaration - which the United States is expected to back - which will be the basis for the alliance's work over the coming years.
Merkel, speaking through an interpreter, said the meeting was an "opportunity to have an exchange about economic developments. and also the future of our trade relations".
Trump has complained bitterly about Europe's lagging defense spending, saying that North Atlantic Treaty Organisation nations were taking advantage of US military largesse at the same time they were offering unfair trade terms to USA businesses.