U.S. President Donald Trumpmet 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.

Turkish President Tayyip Erdogan joined Trump and MbS virtually in the meeting, Turkey's Anadolu News Agency reported.