Princess Rima bint Bandar replaces Prince Khalid bin Salman, the younger brother of the powerful crown prince.
Riyadh: Saudi Arabia on Saturday named a princess as its first woman ambassador to the United States, a key appointment as the fallout over journalist Jamal Khashoggi's murder tests relations between the allies.
Princess Rima bint Bandar replaced Prince Khalid bin Salman, the younger brother of the powerful crown prince who was appointed vice defence minister in a flurry of late-night royal decrees announced on state media.
The reshuffle comes as Saudi Arabia seeks to quell an international outcry over Khashoggi's murder last October in the Saudi consulate in Istanbul, which strained relations with its key ally Washington.
After initially denying they knew anything of Khashoggi's disappearance, the kingdom finally acknowledged that Saudi agents killed him inside the consulate, but described it as a rogue operation.
Princess Rima faces hostile US lawmakers who have threatened to take tough action against Saudi Arabia over the brutal killing amid claims that Crown Prince Mohammed bin Salman -- the de-facto ruler who also serves as the defence minister -- was personally responsible.
The Saudi government has denied he had anything to do with the murder of Khashoggi, a royal insider-turned-critic who was a columnist with the Washington Post.
"The appointment of a new envoy signifies an attempt by Riyadh to try and re-set relations with Washington and draw a line under the Khashoggi affair, however unlikely that may be in practice, at least with Congress," Kristian Ulrichsen, a fellow at Rice University's Baker Institute in the United States, told AFP.
Princess Rima, the daughter of a former long-time ambassador to the United States, has been a leading advocate of female empowerment in the kingdom, which has long faced criticism over its treatment of women.
The princess previously worked at the kingdom's General Sports Authority, where she led a campaign to increase women's participation in sports.
Prince Khalid, a son of the king who served as ambassador since 2017, had been expected to leave Washington for some time -- particularly after the global outcry over Khashoggi tarnished the kingdom's reputation.
His new appointment as deputy defence minister comes as a military coalition led by Saudi Arabia remains bogged down in a four-year conflict in neighbouring Yemen.
It comes around a year after the crown prince, who also serves as the defence minister, announced a military reform plan and a dramatic overhaul of top defence commanders.
"As the Yemen war drags on and the military reform programme continues to move painstakingly slow, Prince Khalid is gaining a difficult portfolio but one that is critical to his father, brother and the kingdom," Becca Wasser, a policy analyst at the US-based RAND Corporation, told AFP.
"Prince Mohammed has struggled to delegate authority within this file which has rendered some efforts -- chiefly military reform -- stagnant, and Prince Khalid's appointment may be an attempt to reinvigorate these initiatives."
Khashoggi's killing has refocused attention on the Saudi-led coalition's bombing campaign in Yemen, which is gripped by what the UN calls the world's worst humanitarian crisis.
Earlier this month, the US House voted overwhelmingly to end American involvement in Saudi Arabia's war effort in Yemen, dealing a rebuke to President Donald Trump who has publicly thrown his support behind the crown prince.
US lawmakers this month also said they were probing whether Trump was rushing to sell sensitive nuclear technology to Saudi Arabia to please corporate supporters who stand to profit handsomely.
The House of Representatives committee has voiced fears that Saudi Arabia could convert US expertise into making a nuclear bomb, heightening already severe tensions with regional rival Iran.