US President Donald Trump heads for Saudi Arabia, Qatar and the United Arab Emirates on Monday, eyeing big business deals even as accords on the Middle East's hotspots will be harder to seal.

While Israel's war in Gaza and Iran's nuclear programme will loom large over Trump's first major foreign trip of his second term, the White House said he looked forward to a "historic return" to the region.

Eight years ago Trump also chose Riyadh for his first overseas trip as president – when he memorably posed over a glowing orb with the leaders of Egypt and Saudi Arabia.

His decision to once more bypass traditional Western allies to visit the oil-rich Gulf states underscores their increasingly pivotal geopolitical role – as well as his own business ties there.

"It's hard for me to escape the idea that President Trump is going to the Gulf because this is his happy place," said Jon Alterman, director of the Middle East programme at the Center for Strategic and International Studies.

"His hosts will be generous and hospitable. They'll be keen to make deals. They'll flatter him and not criticise him, and they'll treat his family members as past and future business partners."

Riyadh, Doha and Abu Dhabi are expected to pull out all the stops for Trump, who's making his first major overseas trip after briefly attending the funeral of Pope Francis in Rome.

The wealthy Arab states will mix pomp and ceremony for the 78-year-old billionaire with deals that could span defense, aviation, energy and artificial intelligence.

But he will not be able to avoid the long list of regional crises, including the war in Gaza, the Huthi rebels in Yemen and Syria's post-Assad turmoil.

The Gulf states have played a key diplomatic role under Trump 2.0. Qatar has been a major broker between Hamas and Israel while Saudi Arabia has facilitated talks on the war in Ukraine.

In Riyadh, Trump will meet the leaders of the six Gulf Cooperation Council states: Saudi Arabia, the UAE, Bahrain, Qatar, Kuwait and Oman. (AFP)