Trump hails Qatari pledge to invest $16b in US air base

Qatar will invest $US10 billion ($A16 billion) in coming years in the Al Udeid Air Base southwest of its capital Doha, the largest US military facility in the Middle East.

In a speech to US troops at the base during his tour of the Gulf, US President Donald Trump also said defence purchases signed by Qatar on Wednesday were worth $US42 billion.

Trump's motorcade had pulled up next to a big hangar at the base after a drive along closed roads and under dusty skies, through a flat desert landscape.

Two bright red Tesla Cybertrucks that belong to Qatar's internal security forces could be seen in the parade of vehicles, according to a shared pool report by AFP news agency.

Trump then headed to the United Arab Emirates, whose leaders are seeking US help to make the wealthy Gulf nation a global leader in artificial intelligence.

The US has a preliminary agreement with the UAE to allow it to import 500,000 of Nvidia's most advanced AI chips a year, starting in 2025, Reuters reported on Wednesday.

The deal would boost the UAE's construction of data centres vital to developing artificial intelligence models.

But the agreement has provoked national security concerns among sectors of the US government, and the terms could change, sources said.

A string of business agreements has been inked during Trump's four-day swing through the Gulf region, including a deal for Qatar Airways to purchase up to 210 Boeing wide-body jets, a $US600 billion commitment from Saudi Arabia to invest in the US and $US142 billion in US arms sales to the kingdom.

The trip has also brought a flurry of diplomacy.

Trump made a surprise announcement on Tuesday that the US would remove longstanding sanctions on Syria and subsequently met Syrian interim President Ahmed al-Sharaa.

He urged Sharaa to establish ties with Syria's longtime foe Israel.

In Abu Dhabi Trump will meet UAE President Sheikh Mohammed bin Zayed Al Nahyan and other leaders.

AI is likely to be a focus of the final leg of Trump's trip.

Former US President Joe Biden's administration had imposed strict oversight of exports of US AI chips to the Middle East and other regions. Among the Biden administration's fears were that the prized semiconductors would be diverted to China and buttress Beijing's military strength.

Trump has made improving ties with some Gulf countries a key goal of his administration.

If all the proposed chip deals in Gulf states, and the UAE in particular, come together, the region would become a third power centre in global AI competition after the United States and China.

Trump had dangled the possibility of making a side trip to Turkey to join Russia-Ukraine talks before returning to Washington, but a US official said on Wednesday that the president would not make that stop.