Saudi Arabia has named an air force pilot son of King Salman as Ambassador to the United States, a major ally with which its ties are improving under President Donald Trump.

The official Saudi Press Agency reported, citing the royal order issued on Saturday, that the Prince Abdullah bin Faisal bin Turki removed as Ambassador to the US and Prince Khaled bin Salman bin Abdulaziz appointed Ambassador.

The US and Saudi Arabia have a decades-old relationship based on the exchange of American security for Saudi oil. But ties between Riyadh and Washington became increasingly frayed during the administration of US president Barack Obama.