DHAKA: Saudi Arabia's Interior Minister, Prince Mohammed bin Nayef, a close friend of the United States and a scourge of Islamist militants, will be the country's first king from the third generation of its ruling dynasty.

King Salman moved swiftly to appoint Mohammed Deputy Crown Prince on Friday, hours after he took the throne following the death of King Abdullah, reports the DNA. The decision appeared to settle for many years to come tough decisions over the kingdom's future succession.

By sending an assassin to try to kill Prince Mohammed when he was Saudi security chief in 2009, al Qaeda paid him the compliment of treating him as one of its most dangerous enemies. The prince narrowly survived that attack, in which a militant approached him claiming he wanted to defect before detonating a bomb concealed under his clothes, and was named Interior Minister in November 2012.

The 55-year-old is now firmly established as the most powerful member of his generation in the ruling al-Saud family, and even before he becomes king will be one of the most important figures in the world's top oil exporter.

He is the first grandson of Saudi Arabia's first monarch, King Abdulaziz, or Ibn Saud, to join the line of succession. He remains in his position as Interior Minister, Friday's decree said.

Yet despite his constant contacts with Western, particularly American, officials and a prominent media presence through his security role, Prince Mohammed remains something of an unknown quantity.

Diplomats and Saudi analysts and academics are uncertain what positions he holds on the big long-term issue facing the kingdom: reconciling social change and a young population with conservative traditions and an oil-dependent economy.

BDST: 0606 HRS, JAN 24, 2015