As Air Force One touched down at Brussels Military Airport, Donald Trump and First Lady Melania were greeted on the tarmac by Belgian Prime Minister Charles Michel and a military fanfare.
The warm reception was in sharp contrast to the mood of protesters on the streets of the capital.
Among the protesters, former marine captain Rudi Vanagt is questioning the priorities of the US President .....
"Instead of building walls, build bridges. And instead of selling more and more military materiel, work for peace."
Mitch Redremer, an American retiree living in Belgium, says President Trump should not be welcomed by Europeans.
"I'm particularly appalled, given that I've been a European resident for a number of years, because he's got the same nationalist ideas that brought about Brexit and some of the other really potentially negative political aspects that could horribly affect continental Europe. I don't think it's the right direction. It's not the right direction for Europe, and it's not even the right direction for the US."
And it's the direction of the US alliance with key European countries that's focusing the attention of Donald Trump as he prepares to meet NATO leaders.
The President once called the western alliance "obsolete" and his secretary of State, Rex Tillerson, also attending the meeting, has foreshadowed some tough talking over the role of NATO and the defence spending of its members.
"As the President has said, he really wants to persuade NATO members to step up and fully meet their obligations under burden-sharing. The two per cent of GDP was a target they all agreed to. I think you can expect the President to be very tough on them and say, 'Look, the US is spending four per cent. We are doing a lot. The American people are doing a lot for your security, for joint security. You need to make sure you're doing your share for your own security as well.' So I think that's going to be the core of his message to NATO."
The US President will visit NATO's new $1.5 billion headquarters and unveil a memorial to the 2001 September 11 attacks in the US.
Donald Trump is nearing the end of his nine-day overseas trip, his first as US leader.
