By Gram Slattery, Pesha Magid and Andrew Mills

RIYADH (Reuters) -U.S. President Donald Trump met with Syria's president in Saudi Arabia on Wednesday and urged him to normalise ties with longtime foe Israel, after a surprise U.S. announcement that it would lift all sanctions on the Islamist-led government. 

Trump met Syria's Ahmed al-Sharaa, who once pledged allegiance to al Qaeda and swept to power at the head of a group that Washington has called a terrorist organisation, before a summit between the United States and Gulf Arab countries.

Photos posted on Saudi state television showed them shaking hands in the presence of Saudi Arabia's Crown Prince Mohammed bin Salman, also known as MbS.

Trump urged Sharaa to join the United Arab Emirates, Bahrain and Morocco, which normalised relations with Israel under the U.S.-brokered Abraham Accords in 2020, the White House press secretary posted on X.

The United States also hopes Saudi Arabia will join the Abraham Accords, but discussions came to a halt after the Gaza war erupted and the kingdom insists there can be no normalisation without Palestinian statehood.

Trump said on Tuesday Saudi Arabia would join the accords in its own time.

Despite concerns within sectors of his administration over Syria's leaders' former ties to al Qaeda, Trump said on Tuesday he would lift sanctions on Syria in a major policy shift. 

He also said Washington was exploring normalising relations with Syria's government beginning with his meeting with Sharaa.

BOOST FOR SYRIA'S NEW LEADERS

The lifting of sanctions came despite deep Israeli suspicion of Sharaa's administration. Israeli officials have continued to describe Sharaa as a jihadist, though he severed ties with al Qaeda in 2016. The Israeli prime minister's office did not immediately respond to a request for comment.

The decision is a boost for Sharaa, who has been struggling to bring the country under the control of the government after toppling former President Bashar al-Assad in December.

Removing U.S. sanctions that cut Syria off from the global financial system will clear the way for greater engagement by humanitarian organizations and will ease foreign investment and trade as the country rebuilds from a civil war.

Saudi Arabia's Foreign Minister Prince Faisal bin Farhan Al-Saud told a press conference that Riyadh will support Syria's economic recovery and that there are many investment opportunities in the country after sanctions are lifted.

U.S. ally Israel opposes sanctions relief for Syria and has escalated military strikes there since Assad was toppled, saying it will not tolerate an Islamist presence in southern Syria.

The challenges facing Syria's new government were also laid bare in March when Assad loyalists assailed government forces, prompting attacks in which Islamist gunmen killed hundreds of civilians from the Alawite minority, drawing U.S. condemnation.

Trump said his trip to the Middle East does not sideline Israel, after he bypassed Israeli officials during his tour.

The trip is the latest development to sow doubt in Israel about where the country stands in Washington's priorities, as the U.S. moves forward with its nuclear talks with Iran. Israel considers Iran's nuclear program "an existential threat."

Trump told reporters the fact he has relationships with countries in the Middle East is "very good for Israel".

He said the meeting with Sharaa, who he described as a young, attractive guy with a very strong past, was "great".

"He's got a real shot at holding it together," said Trump.

Sharaa was for years the leader of al Qaeda's official wing in the Syrian conflict. He first joined the group in Iraq, where he spent five years in a U.S. prison. The United States removed a $10 million bounty on his head in December.

The Syrian foreign minister said on Wednesday the meeting between Trump and Sharaa included discussions about combating terrorism and cooperation in eliminating the influence of armed groups that threaten Syrian stability, including Islamic State.

This meeting will be followed by another between the Syrian foreign minister and his U.S. counterpart Marco Rubio.

BUSINESS DEALS

Trump's first day of a four-day swing through the Gulf region brought a $600 billion commitment from Saudi Arabia to invest in the U.S. and $142 billion in U.S. arms sales to the kingdom. 

Later on Wednesday, Trump flew to the Qatari capital Doha, which is also expected to announce hundreds of billions of dollars in investments in the U.S.

Trump isolated Qatar in 2017, when he lent initial support to a trade and diplomatic embargo that Saudi Arabia, the United Arab Emirates, Bahrain and Egypt imposed on Doha, one of the worst crises Qatar had ever faced.

Gas-rich Qatar has since rehabilitated itself in the eyes of the United States. It punches above its weight in investments and diplomacy and this is the first visit to Qatar by a U.S. president in 23 years.

A pair of bright red Tesla Cybertrucks carrying the markings of Qatar's Emiri Guard police force accompanied Trump's motorcade from the airport to the Emiri Diwan.

Qatar Airways was expected to disclose a deal to buy around 100 widebody jets from Boeing, a source familiar with the matter said. 

(Reporting by Gram Slattery, Pesha Magid and Andrew Mills; Writing by Michael Georgy; Editing by Sharon Singleton, William Maclean)