The comments will have made for uncomfortable viewing for the rest of Nato's 29 members, whose officials have voiced fears that Mr Trump could undermine the alliance during the gathering.
U.S. Senator Bob Corker of Tennessee, a Republican who chairs the Senate Foreign Relations Committee, said he hoped Trump avoided a repeat of his G7 summit in Quebec City, when his demands on reducing trade surpluses with the United States prompted a bitter debate with allies. "But other presidents never did anything about it because I don't think they'd up it or wanted to get involved", Trump said.
"I have the United Kingdom, which is in somewhat turmoil, and I have Putin", Trump said.
Trump meets Russian President Vladimir Putin in Helsinki on July 16 the final stop of his European trip.
But instead of trying to engage with what Trump actually said during the Fox News interview, Gardner pretended Trump actually meant the opposite of what he said.
America's North Atlantic Treaty Organisation partners will expand military outlays by a combined 3.82 percent in 2018, bringing the cumulative rise since the start of 2015 to more than $87 billion, according to the alliance, which Trump is due to visit for a two-day summit starting Wednesday.
Trump has said maintaining a strong personal relationship with Putin is in America's interest and has signaled to allies that he trusts his own instincts in dealing with Russia's president.
This is not the first time Trump has taken aim at Nord Stream 2.
Trump's criticism of the alliance has stood in stark contrast with his warm words for NATO's main adversary, Russia.
She added that "Trump is also bringing Putin a "little" present-why 'little, ' I don't know".
Mr Stoltenberg also stressed how "even during the Cold War, NATO allies were trading with Russia".
Germany's defence minister Ursula von der Leyen denied it was a prisoner of Russian policy, and defended keeping a communication line with Russia.
The U.S. has opposed the project because of its political implications, but work has begun regardless.
"So, we're going to have a meeting on that and the secretary general has worked very hard on that, he understands the problem and hopefully we can get it resolved".
Donald Trump speaks to media before leaving the White House for Europe.
"Dear America, appreciate your allies - after all, you don't have that many", Tusk added, and also urged European countries to "spend more on your defense because everyone respects an ally that is well-prepared and equipped". "Who would think?" he told reporters.
"So, we're protecting Germany, we're protecting France, we're protecting all of these countries", the president said.
Mrs May said: "Nato is as vital today as it ever has been and our commitment to it remains steadfast".
Of his meetings in Brussels and Britain and with Putin, he said: "Frankly, [the meeting with] Putin may be the easiest of them all - who would think?"