When Donald Trump barged past the leader of NATO's next member to bask in the media spotlight at the alliance's summit, footage of the incident soon flooded the internet.
A theme that runs through the summit is the showcasing of North Atlantic Treaty Organisation to Mr. Trump, who had called the alliance "obsolete" during his presidential campaign, although he reversed his position during Mr. Stoltenberg's visit to the White House earlier this year.
"Some issues remain open, like climate and trade. And I am not 100 percent sure that we can say today - "we" means Mr. President and myself - that we have a common position, common opinions about Russian Federation", said Tusk.
The small Balkan country will formally become NATO's 29th state in June but Markovic joined the Brussels summit, Trump's first, and a ceremonial opening of the alliance's new headquarters.
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.
A new strain emerged on the relationship between the US and a key European ally: a British official said Thursday that police in Manchester will stop sharing information about their bombing investigation with the USA until they get a guarantee that there will be no more leaks to the news media. The source of the leak is unclear.
During his election campaign, Mr Trump repeatedly called for tougher screening of immigrants to the USA, even though the process for refugees from countries such as Syria or Somalia can take up to five years.
Trump irritated European Union leaders during his election campaign a year ago by hailing Brexit and suggesting other countries might follow Britain out of the 28-nation bloc. "It was for me a very positive moment in our discussions".
Finishing off a long day, Trump arrived late Thursday night in Sicily for meetings Friday with leaders from the Group of 7 wealthy nations.
NATO's chief affirmed that the alliance countries will join the worldwide coalition fighting the Islamic State extremist group but will not wage direct war against the extremists. The move, which is expected during Thursday's meeting, is symbolically important, especially since the terror group claimed responsibility Tuesday for a deadly explosion at an Ariana Grande concert in Manchester, England.
The leaders also endorsed the appointment of an anti-terror coordinator to oversee their efforts, and made a decision to increase the number of flight hours of a surveillance plane watching the skies over northern Iraq and Syria.
Praise was always going to be in short supply after Trump's sharp election campaign criticism of the alliance, which he blamed for not doing more to combat terrorism. "NATO members must finally contribute their fair share and meet their financial obligations". "First and foremost on counter-terrorism and I am sure I don't have to explain why, but some issues remain open, like climate and trade", Tusk, who represents the 28 leaders of the European Union, said.
While in Belgium, Trump will unveil a memorial to the terrorist attacks of September 11, 2001, the only time in the alliance's history that the Article 5 mutual defense pledge has been invoked.
It's a reminder of Nato's commitment to its collective defence clause so called Article 5 which commits allies to defend any of the 28 members that come under attack.
But EU officials were pleased he was fitting in the visit at all and noted that his critical tone had changed after meeting with German Chancellor Angela Merkel in Washington and after sending U.S. Vice President Mike Pence to Europe this year.
The long day of Brussels meetings was a stark contrast to his friendlier Middle East encounters, where Trump embraced the authoritarian Saudi monarchy and said he had been wowed by Saudi King Salman's wisdom. Protests were slated to take place outside the heavily guarded security perimeter near the city's airport and downtown.