Trump's Twitter post on Tuesday echoed those on Monday and his criticism at a rally of supporters in the United States last week in which he said that Washington was unfairly carrying nearly all the cost of defending Europe.
In March 2016 he said it was "obsolete and disproportionately too expensive" and on Monday, ahead of the summit, he suggested (on Twitter, of course), that "by some accounts, the U.S. is paying for 90% of Nato" and on Tuesday raged: "NATO countries must pay MORE, the United States must pay LESS".
While defense spending has increased across the alliance, Trump says not enough has been done.
In a pointed apparent reference to Mr Trump's meeting with Mr Putin, Mr Tusk noted that European military spending "is an investment in our security, which can not be said with confidence about Russian and Chinese spending". "I think that getting along with Russian Federation, getting along with China is a good thing, getting along with others is a good thing". The U.S.is spending many times more than any other country in order to protect them.
Looking for signs that the president remained committed to the alliance, Mr Stoltenberg pointed to a rise in American presence in Europe as well as a spending increase of 40 per cent on defence in Europe since the U.S. president's inauguration. The United States, with the biggest economy, pays the biggest share - 22.1 percent.
For his part, Commission chief Jean-Claude Juncker remarked that "NATO and the European Union are the most natural of partners", adding that the EU executive had proposed a dramatic increase in defence spending in its draft 2021-2027 budget. But it is more than reasonable to question whether the transatlantic military alliance can continue taking on so many tasks at the same time-many of which have nothing to do with preserving a Europe whole, free, and at peace.
"Disparaging long-standing allies at the same time as talking up the country that has wantonly seized territory and redrawn Europe's borders by military force for the first time since World War Two is disconcerting to say the least", said Boudreau.
World Health Organization got Trumped over breastfeeding resolution
Russian Federation ultimately sponsored the resolution and the American delegation did not issue any threats to the country. Hundreds of government delegates had gathered at the United Nations-affiliated World Health Assembly in Geneva in May.
Asked by reporters if he considers Putin a friend or foe, Trump answered, "competitor". This is not fair, nor is it acceptable.
"I am confident that North Atlantic Treaty Organisation will once again be able to prove that we can stand united because we have seen that before but also because it's in our interests to stand united".
Trump, who has compared the sentiment that underpinned the Brexit vote to leave the European Union to his own election, will be making his maiden presidential trip to Britain at a fraught time for May.
European Council President Donald Tusk set the scene by warning Mr. Trump that he is losing friends fast.
Asked whether Mr Putin is a friend or a foe, Mr Trump said, "I really can't say right now" before calling Russian Federation a "competitor". "We will also work together to respond to hybrid threats and to counter terrorism", Stoltenberg said. But we can not be taken advantage of. "It's not a bad thing, I've said that many times".
Increasing defense spending "does not happen overnight", Smith said.
Furthermore, all member states contribute to NATO's overall budget based on their national income, with the U.S. providing about 22% of the budget.