North Atlantic Treaty Organisation leaders from 28 allied countries gathered here for their first meeting at NATO's new headquarters in Brussels, with military spending, counterterrorism on the agenda.
At NATO's gleaming new headquarters, Trump returned to his longstanding call for member nations to pay their fair share, lecturing leaders like German chancellor Angela Merkel and new French President Emmanuel Macron about contributing more as they stood listening in awkward silence.
"This is not fair to the people and taxpayers of the United States, and many of these nations owe massive amounts of money from past years", Trump said as the other leaders watched.
Some of the allies - particularly Eastern European nations deeply anxious about Russian aggression - were hopeful that Trump would state a firm commitment to NATO's Article 5 mutual defense agreement, which underpins the entire alliance. Tusk also called for "Western values" to be promoted, challenging former tycoon Trump's world view that self-interested deals best settle worldwide problems. Mr. Trump also had to reckon with the anger of UK Prime Minister Theresa May, who is upset over the leak to the US media of British intelligence on the Manchester attack.
In a second blow, the president declined to commit the United States would stay in NATO's mutual defense pact. And Macron pushed Trump on a sweeping climate agreement and even engaged in an apparent handshake stand-off. He appeared to shamelessly shove Montenegro Prime Minister Dusko Markovic out of the way so he could be at the front of a group photo. Traveling on Air Force One this week, Secretary of State Rex W. Tillerson told reporters, "Of course we support Article 5".
In the Middle East, President Donald Trump was feted with pageantry, the leaders of Saudi Arabia and Israel seemingly in competition to outdo the other with the warmth of their welcomes and the depth of their pledges of cooperation.More news: Rouhani says Iran "heedless" of pressure to continue missile program
The president also held private meetings. Tamara Keith, NPR News, traveling with the president. The pontiff had also been the subject of Trump's ire he called Francis a "disgrace" for questioning his faith while criticizing his border wall plan but the president said it was the "honor of a lifetime" to meet the pope at the Vatican.
On one hand, the president's remark that "23 of the 28 member nations are still not paying what they should be paying and what they're supposed to be paying for their defense" is accurate.
Tusk had earlier said there were differences on climate change and trade but above all Russian Federation.
"You know, Mr President, we have two presidents in the EU", Tusk said as they started their meeting.
President Donald Trump speaks during a meeting with Belgian Prime Minister Charles Michel at the Royal Palace, Wednesday, May 24, 2017, in Brussels. The leaders were lining up to take a "family photo", as is tradition at such summits.