"(Former) President (Barack) Obama raised the issue in a constructive and collegial way that succeeded in securing a pledge from North Atlantic Treaty Organisation members to increase their defence spending, without undermining the cohesion of the alliance in the process", Kerry said.
The 29 allies are due to restate a commitment to try to spend two percent of GDP on defense by 2024, according to excerpts of their final summit declaration seen by AFP.
"Many countries are not paying what they should, and, frankly, many countries owe us a tremendous amount of money from many years back", Trump said at a breakfast meeting with NATO Secretary-General Jens Stoltenberg.
"Germany goes out and pays billions and billions of dollars a year to Russian Federation", said Trump.
Allies were aware of Trump's grievances ahead of the summit, but he specifically rattled Germany ahead of his full day of meetings in Brussels when he called them out over the controversial $12 billion proposed Nord Stream 2 pipeline between Russian Federation and Germany and suggested it puts the entire historic alliance in question. Coal remains a bedrock energy source for Germany despite its hope to wean itself from that mineral, and nuclear plants have several years of life before they are to be phased out.More news: Schumer, Pelosi Slam Trump Over Germany Remarks: 'An Embarrassment'
She recalled her own youth in Soviet-dominated East Germany and said she was "very happy that today we are united in freedom, the Federal Republic of Germany".
In 2017, the United States spent 3.1 percent of its GDP on defense, while Estonia, Greece, Poland and the United Kingdom stand as the only countries which have crossed the two percent threshold.
"We have had discussions, we do have disagreements, but most importantly we have decisions that are pushing this alliance forward and making us stronger". "The good news is that we are making progress".
"The alliance is very important and I think there's ways of communicating our displeasure with things without trying to insult and break the alliance apart", said Corker.
The mood was already prickly ahead of the summit, prompting a terse exhortation from the European Union's President Donald Tusk for Trump to "appreciate" his allies and reminding him that Europe had come to its aid following the 9/11 attacks.
President Trump publicly criticized Germany over its Baltic Sea gas pipeline deal with Russian Federation, calling the wealthiest nation in the European Union "a captive to Russian Federation". On 17 May, the Wall Street Journal reported that Trump is demanding that Germany drop Nord Stream 2 as one of the conditions for a trade deal with Europe that would not include high tariffs on steel and aluminium.