Starting with his tightly-scheduled meetings with European Union leaders on Thursday in Brussels, US President Donald Trump and EU leaders are expected to start swirls of bargains on how to reshape the trans-Atlantic partnership and lead the changing world.

Trump, who called Brussels a "hellhole" during his election campaign, is expected to arrive in the Belgian capital and EU headquarters amid "not welcome" protests in Rome and Brussels on Wednesday, after his whirlwind visits to Israel, Saudi Arabia and a meeting with Pope Francis in Rome.

During his stay in Brussels, he is scheduled to meet the Belgian king and prime minister on Wednesday, take part in a EU-US leaders' meeting, and "compare opinions" with new French President Emmanuel Macron over lunch before attending the NATO leaders summit on Thursday afternoon. He will then fly to Italy to attend the G7 summit on Friday and Saturday.