Saudi Arabian spy chief Prince Bandar bin Sultan was removed from his post, state media reported on Tuesday.

According to the Saudi Press Agency, Bandar, who was appointed in 2012 mainly to oversee the kingdom’s efforts to help topple Syrian president Bashar al-Assad, was replaced at his own request. No further details were given.

Bandar previously served as Saudi Arabia’s ambassador to the United States for more than thirty years. He was also closely involved in Arab Gulf states’ support for Egypt’s military rulers after they ousted the Islamist president Mohamed Morsi last year.

While his appointment as intelligence chief was initially seen as a positive for the kingdom’s most important Western ally, with The Washington Post‘s David Ignatius describing him as “especially well placed to manage intelligence liaison with the United States,” Saudi Arabia’s growing frustrating with the Obama Administration’s unwillingness to do more to help remove Assad in Syria and support the army coup in Egypt led Bandar to warn of a “major shift” in his country’s foreign relations, away from the United States, in October.

The Saudis are also worried about America’s outreach to their nemesis Iran, fearing that it will trade a nuclear deal for continued Iranian influence in Iraq, Lebanon and Syria.

Since the fall of Iraq’s Saddam Hussein in 2003 and Egypt’s Hosni Mubarak three years ago, the Saudis see themselves as the only Sunni power strong enough to withstand Shia Iran’s expanding influence in the Middle East. The two are locked in a struggle for regional hegemony that is informed by contrasting religious views: the Saudis as the guardians of Mecca and conservative Sunni hierarchy; the Iranians as the vanguard of an Islamic revolution.

Syria’s dictator Bashar Assad is Iran’s only Arab ally — which is why Saudi Arabia supports the largely Sunni uprising against his regime.

Similarly, in Iraq, Iran sponsors the government of Shia prime minister Nouri al-Maliki who has sidelined Sunni politicians.

In neither conflict do the Saudis perceive the United States to be as strongly motivated as they are to preserve a favorable balance of power in the region.