Saudi Arabia has removed Muhammad bin Nayef as the crown prince and replaced him with defence minister Mohammed bin Salman in a dramatic changeover in the ultra-conservative kingdom's royal family. Bin Salman, 31, son of King Salman bin Abdulaziz, was previously the country's deputy crown prince.

Bin Nayef, the king's nephew and a familiar face in Washington, was overseeing Saudi Arabia's powerful interior ministry in charge of the security affairs of the kingdom. He has now been removed from all his official posts.

According to a royal decree released on Wednesday, 21 June, from Riyadh and carried by the state-run Saudi Press Agency, bin Salman, 31, has also been appointed as the deputy prime minister and will retain his defence portfolio. His quick rise to become the first in line to the throne was suspected to be in the pipeline for some time.

The restructuring of the Saudi monarchy is expected to have far-reaching implications not just for the kingdom, the Arab world's largest economy, but also across the Middle East. This is because Mohammed bin Salman, known by his nickname MBS in the power circles, is widely seen as the ambitious architect of Riyadh's attempt in overhauling its economy by making it less dependent on oil.

Even before the elevation, bin Salman was also instrumental in dictating the kingdom's energy policy and was responsible for running Riyadh's war in Yemen. Though bin Salman remained relatively unknown until his father became the ruler in 2015, the prince has made efforts in the last years to build his profile through interviews to Western media.

Bin Salman's meteoric rise was visible both inside and outside Saudi Arabia as he gradually went on to become the kingdom's most prominent official in little more than a year.

Thirty-one of the 34 members of Saudi Arabia's succession committee voted for bin Salman to be the next successor, the royal decree read. King Salman has called for a public pledging of allegiance to the newly inaugurated crown prince in Mecca later in the day.

The surprise shake-up has also seen several other top royal figures being realigned to new posts. It comes just as the volatile region is undergoing a turbulent period after key Arab states led by Riyadh launched a campaign to diplomatically isolate Qatar. Saudi Arabia is also facing increasing frictions with Iran and is currently locked in a bitter conflict in Yemen.