Saudi Arabia’s intelligence chief, Prince Bandar bin Sultan, has resigned from his post with immediate effect and has been replaced by his deputy Yousef al-Adrissi.

The mercurial official was appointed to the role in 2012, but a long bout of illness meant he has been absent from the kingdom for the past few months.

Prince Bandar was replaced in February by Saudi Arabia’s interior minister, Prince Mohammed bin Nayef, as the leading figure in the kingdom’s efforts to fund and arm opposition forces in Syria. No official reason was given for Prince Bandar being relieved of his Syria remit, but the move was seen as a clear strategy to align both domestic and external policies aimed at fighting extremism and terrorism.

Riyadh has serious concerns about Saudi citizens returning from Syria and turning their attention to domestic terrorism.

Other issues were said to be a series of failed diplomatic missions with several of Riyadh’s key allies. These included the failure to convince the US to carry out air-strikes in Syria, as well as infuriating Russia by inferring Saudi Arabia aided Islamic terrorism in Chechnya.  

Al-Adrissi’s appointment is not believed to be permanent and an official replacement from the royal family is expected to be announced shortly.